GMEOW — Global Metadata and Entity Ontology for the Web
type: Ontology
version IRI: https://blackcatinformatics.ca/gmeow/0.1.0
rights: Copyright © 2026 Blackcat Informatics® Inc. Licensed under CC BY 4.0; also available under separate proprietary terms from Blackcat Informatics Inc.
created: 2026-06-03
creator: Blackcat Informatics Inc.
description: A reasoning-centric, OWL 2 DL, upper-ontology-grounded super-vocabulary that unifies document metadata, entity descriptions, legal agreements, contacts and person-centric data. GMEOW is grounded in gUFO and aligned to FOAF, REL, DOAP, PROV-O, schema.org and Wikidata.
license: https://creativecommons.org/licenses/by/4.0/
modified: 2026-06-04
publisher: Blackcat Informatics Inc.
preferred namespace prefix: gmeow
preferred namespace uri: https://blackcatinformatics.ca/gmeow/
label: GMEOW
version info: 0.1.0

confidence
type: AnnotationProperty
definition: Confidence in a claim, in the closed interval [0,1], attached to the statement it qualifies.

importance level
type: AnnotationProperty
definition: Relative import/source importance of a claim on a 0–10 scale; projection takes the maximum across imports.

mapped from
type: AnnotationProperty
definition: The source property a claim was derived from during ingestion, recorded for mapping-step audit.

valid from
type: AnnotationProperty
definition: The instant from which the annotated statement is asserted to hold.
range: dateTime

valid until
type: AnnotationProperty
definition: The instant until which the annotated statement is asserted to hold.
range: dateTime

broughtAbout
type: ObjectProperty
domain: Event
range: Situation
comment: Identifies a gufo:Situation that is brought about by the gufo:Event. Guizzardi et al. (2013) included a notion of "brings-about" that related events to a single ("maximal") situation, embodying all the effects of the event at the time it ends. This implementation of gufo:broughtAbout diverges from "brings-about" in that work because gufo:broughtAbout can be used to relate events to more than one gufo:Situation. Each gufo:Situation identified through gufo:broughtAbout should be understood as an (improper) part of the maximal situation.

categorizes
type: ObjectProperty
domain: Class
  intersection of: Type
  intersection of: Class
    complement of: AbstractIndividualType
  intersection of: Class
    complement of: ConcreteIndividualType
range: Type
comment: Identifies a gufo:Type whose instances may be classified by instances of the categorizing higher-order type. For example, "ShipType" gufo:categorizes "Ship". Instances of "ShipType" such as "Supercarrier" and "Cargoship" should be declared subclasses of "Ship". OWL 2 punning should be used to capture the two facets of "Supercarrier" and "Cargoship" in this example: (i) as instances of "ShipType", and (ii) as subclasses of "Ship". The categorized type is termed the "base type" in the "powertype pattern" see Carvalho et al (2017), the higher-order type is often called the "powertype". gufo:categorizes is the general (unspecific) form of categorization. See gufo:partitions for a more specific form, in which instances of the categorized type are classified by exactly one instance of the higher-order type. The domain is gufo:Type excluding gufo:AbstractIndividualType as well as gufo:ConcreteIndividualTypes because those types are first-order types (their instances are individuals). Only instances of gufo:Type representing higher-order types can categorize a base type. For further details and formalization of "categorization", see Carvalho et al (2017) which combines UFO with MLT (a multi-level modeling theory). V. A. Carvalho, J. P. A. Almeida, C. M. Fonseca, and G. Guizzardi, “Multi-level ontology-based conceptual modeling,” Data & Knowledge Engineering, vol. 109, p. 3–24, 2017. <http://dx.doi.org/10.1016/j.datak.2017.03.002>

concernsConstitutedEndurant
type: ObjectProperty
domain: TemporaryConstitutionSituation
range: Endurant
comment: Identifies the constituted gufo:Endurant in the gufo:TemporaryConstitutionSituation.

concernsNonRigidType
type: ObjectProperty
type: FunctionalProperty
domain: TemporaryInstantiationSituation
range: NonRigidType
comment: Identifies the gufo:NonRigidType that is instantiated by the endurant that stands in a gufo:TemporaryInstantiationSituation.

concernsQualityType
type: ObjectProperty
type: FunctionalProperty
domain: QualityValueAttributionSituation
range: EndurantType
comment: Identifies the quality type (a gufo:EndurantType subclassing gufo:Quality) whose value is attributed in the gufo:QualityValueAttributionSituation.

concernsReifiedQualityValue
type: ObjectProperty
type: FunctionalProperty
domain: QualityValueAttributionSituation
range: QualityValue
comment: concernsQualityValue
comment: Identifies the gufo:QualityValue (i.e., the reified quality value) associated with the endurant that stands in the gufo:QualityValueAttributionSituation.

concernsRelatedEndurant
type: ObjectProperty
type: FunctionalProperty
domain: TemporaryRelationshipSituation
range: Endurant
comment: Identifies the related gufo:Endurant in the gufo:TemporaryRelationshipSituation.

concernsRelationshipType
type: ObjectProperty
type: FunctionalProperty
domain: TemporaryRelationshipSituation
range: RelationshipType
comment: Identifies the gufo:RelationshipType instantiated in the gufo:TemporaryRelationshipSituation.

concernsTemporaryWhole
type: ObjectProperty
type: FunctionalProperty
domain: TemporaryParthoodSituation
range: Endurant
comment: Identifies the whole (a gufo:Endurant) of which the endurant that stands in the gufo:TemporaryParthoodSituation is part.

constitutes
type: ObjectProperty
domain: ConcreteIndividual
range: ConcreteIndividual
comment: Identifies a gufo:ConcreteIndividual that is constituted (partially) by the constituent individual. For example, the gufo:Collection of persons whose members are John, Paul, George, Ringo constituted the beatles, the gufo:Quantity of marble that constitutes the statue of Venus de Milo, and the gufo:Event of Paul raising his arm in a meeting that constitutes his voting (also a gufo:Event). In case constitution changes in time, see gufo:standsInQualifiedConstitution.

contributedToTrigger
type: ObjectProperty
domain: Situation
range: Event
comment: Identifies a gufo:Event that the gufo:Situation contributed to trigger. Guizzardi et al. (2013) defined a notion of "triggers" to relate the situation satisfying all the sufficient and necessary conditions with the triggered event. This implementation differs from "triggers" as defined in that work because gufo:contributedToTrigger can be used to relate more than one gufo:Situation to a gufo:Event. Each gufo:Situation identified through gufo:contributedToTrigger should be understood as an (improper) part of the situation that triggered the event.

externallyDependsOn
type: ObjectProperty
type: IrreflexiveProperty
domain: ExtrinsicMode
range: Endurant
comment: Identifies a gufo:Endurant on which the gufo:ExtrinsicMode depends. For example, John's duty to return the book he borrowed from Mary (a gufo:ExtrinsicMode) depends externally on Mary. The identifed gufo:Endurant should be external to the bearer of the extrinsic mode (see Guizzardi, 2005, p. 239). In other words, the identified endurant should not be a part or an intrisic aspect of the bearer of the extrinsic mode.

hasAssociatedQualityValueType
type: ObjectProperty
domain: EndurantType
range: AbstractIndividualType
comment: Identifies a quality value type to which the quality type is associated. For example, a "Color" quality type may be associated with a "ColorValueInRGB" quality value type. It relates a specialization of gufo:Quality (an instance of gufo:EndurantType) to a specialization of gufo:QualityValue (an instance of gufo:AbstractIndividualType). To be used only when quality values are reified.

hasBeginPoint
type: ObjectProperty
domain: ConcreteIndividual
range: Instant
comment: Identifies the begin point for a gufo:ConcreteIndividual, in the case in which time instants are reified. In the case of endurants, this identifies the time point when the endurant comes into existence. In the case of events, this identifies the time point when the event starts to take place. In the case of situation, this identifies the time point when the situation begins to hold. If time instants are not reified, use gufo:hasBeginPointInXSDDate or gufo:hasBeginPointInXSDDateTimeStamp.

hasEndPoint
type: ObjectProperty
domain: ConcreteIndividual
range: Instant
comment: Identifies the end point for a gufo:ConcreteIndividual, in the case in which time instants are reified. In the case of endurants, this identifies the time point when the endurant ceases to exist. In the case of events, this identifies the time point when the event ends. In the case of situation, this identifies the time point when the situation ceases to hold.

hasReifiedQualityValue
type: ObjectProperty
domain: ConcreteIndividual
range: QualityValue
comment: Identifies an instance of gufo:QualityValue to reflect the perception or conception of a quality in a certain value space. Use this property only for quality values that are to be reified in the A-box and associated with a gufo:ConcreteIndividual. Otherwise, use the gufo:hasQualityValue data property and a literal to determine the quality value. The full representation pattern for quality values involves first identifying a gufo:Quality that inheres in a concrete individual and then associating it with a reified quality value. For example, let us consider the color of Yves Klein's "Blue Monochrome" painting made in 1961 (MoMA's object with number 618.1967). In the full pattern, an instance of gufo:Quality that inheres in the physical object (the color of that painting) is associated with a gufo:QualityValue (say the triplet <0, 47, 167> for that painting) through gufo:hasReifiedQualityValue. The full pattern is recommended when different quality spaces are expected to be used for the same quality. For example, the color of that painting could also be associated with a quadruple <100, 72, 0, 35> representing the same color in a CMYK space. When the full pattern is not required, gufo:hasReifiedQualityValue can also be used to directly associate a concrete individual (without identifying the quality) with a quality value.

historicallyDependsOn
type: ObjectProperty
type: TransitiveProperty
domain: ConcreteIndividual
range: ConcreteIndividual
comment: Identifies a gufo:ConcreteIndividual on which the concrete individual depends historically. For example, a person is historically dependent on his/her ancestors. When used between events, historical dependence encompasses causation (when the event is caused by the other), but also other cases where there is dependence but not causation (when the event brings about a situation that is either insufficient or more than sufficient to trigger the historically dependent event). For example, Real Madrid's goal in the 60th minute of the 2016 FIFA Club World Cup Final is historically dependent on (and in this case caused by) a penalty kick by Cristiano Ronaldo. The penalty kick itself is historically dependent on (but not caused by) a penalty (the occurrence of the penalty is necessary but not sufficient to cause the penalty kick as authorization of the referee is required). Historical dependence is transitive. Hence, in the example above, Real Madrid's goal is historically dependent on the penalty.

inheresIn
type: ObjectProperty
type: FunctionalProperty
type: AsymmetricProperty
type: IrreflexiveProperty
domain: Aspect
range: ConcreteIndividual
comment: Identifies the gufo:ConcreteIndividual in which the gufo:Aspect inheres. Inherence is a sort of existential dependence. The identified concrete individual is the "bearer" of the aspect. For example, the color of an object inheres in the object and the average speed of a flight inheres in the flight.

isAspectProperPartOf
type: ObjectProperty
sub property of: isProperPartOf
type: TransitiveProperty
domain: Aspect
range: Aspect
comment: Identifies a gufo:Aspect of which the aspect is a proper part. For example, John's obligations towards Mary in the scope of their marriage is an aspect proper part of their marriage (and same can be said of Mary's extrinsic aspects in the scope of their marriage.) This property can be used to represent the composition of a relator from extrisinc aspects, but also to represent complex extrisinc aspects. gufo:isAspectProperPartOf is transitive.

isCollectionMemberOf
type: ObjectProperty
sub property of: isObjectProperPartOf
domain: Object
range: Collection
comment: Identifies a gufo:Collection of which the object is a member. This is the relation between John and a group of persons, and between a cow and its herd. gufo:isCollectionMemberOf is intransitive (Guizzardi, 2005, p. 185). For membership in a gufo:VariableCollection, see gufo:standsInQualifiedParthood.

isComponentOf
type: ObjectProperty
sub property of: isObjectProperPartOf
domain: Object
range: FunctionalComplex
comment: Identifies a gufo:FunctionalComplex of which the object is a component. For example, the habitation module is a component of the International Space Station, and so are each of the solar panels; Obama's brain is a component of his body, and so is his heart; the engine is a component of the HMS Queen Elizabeth (R08). gufo:isComponentOf is not transitive in the general case. Particular sub-properties may be transitive (Guizzardi, 2005, p. 183). When a component may change its relation to be whole, see gufo:standsInQualifiedParthood.

isDerivedFrom
type: ObjectProperty
domain: Class
  union of: ComparativeRelationshipType
  union of: MaterialRelationshipType
range: EndurantType
comment: Identifies a gufo:EndurantType from which the material or comparative relation can be derived. The identified gufo:EndurantType should be a subclass of gufo:Aspect, more specifically a subclass of gufo:ExtrinsicAspect in the case of a gufo:MaterialRelationshipType, and a subclass of gufo:IntrinsicAspect in the case of a gufo:ComparativeRelationshipType. For example, "marriedWith" can be derived from "Marriage", "heavierThan" can be derived from "Weight". See Fonseca et al. (2019).

isEventProperPartOf
type: ObjectProperty
sub property of: isProperPartOf
type: TransitiveProperty
domain: Event
range: Event
comment: Identifies a gufo:Event of which the event is part. For example, Cristiano Ronaldo's penalty kick is an event proper part of the 2016 FIFA Club World Cup Final, having ocurred in the 60th minute of that match. That match is itself an event proper part of the 2016 FIFA Club World Cup. The match can be decomposed in different ways. For example, we can identify the participation of each player in the match (instances of gufo:Participation that are proper parts of the match) or decomposed the match using some temporal segmentation (each minute of the match, each of which is a proper part of the match). gufo:isEventProperPartOf is transitive.

isObjectProperPartOf
type: ObjectProperty
sub property of: isProperPartOf
type: TransitiveProperty
domain: Object
range: Object
comment: Identifies a gufo:Object of which the object is a part. This is a general parthood relation between objects. Use the various sub-properties provided in order to represent specific types of parthood, each of which has specialized semantics (and different formal properties in this implementation, in particular, transitivity (Guizzardi, 2005, section 5.6).

isProperPartOf
type: ObjectProperty
type: TransitiveProperty
domain: Thing
range: Thing
comment: Identifies a whole of which the entity is a proper part. gufo:isProperPartOf is the most generic parthood relation in this implementation. Use the various sub-properties provided in order to represent specific types of parthood. Proper parthood (and each of its sub-properties) is asymmetric and irreflexive. Nevertheless, these characteristics are not declared in this implementation since that would violate rules of OWL 2 DL that guarantee decidability of reasoning. Instead, we have focused only on declaring transitivity where applicable. Note that gufo:isProperPartOf (as the most general notion of parthood) is transitive, although the various sub-properties may not be transitive.

isSituationProperPartOf
type: ObjectProperty
sub property of: isProperPartOf
domain: Situation
range: Situation
comment: Identifies a gufo:Situation of which the situation is a part. Examples include: the situation in which John has influenza is part of the situation in which John has influenza and he is tired; the situation in which John is friends with Mary is part of the situation in which he is friends with Mary and Alice; the situation in which John is married to Alice is part of the situation in which John is married to Alice, while she works at the Free University of Bozen-Bolzano.

isSubCollectionOf
type: ObjectProperty
sub property of: isObjectProperPartOf
type: TransitiveProperty
domain: Collection
range: Collection
comment: Identifies a gufo:Collection of which the collection is a sub-collection. All members of the sub-collection are members of the identified super-collection. gufo:isSubCollectionOf is transitive (Guizzardi, 2005, p. 186). For parthood involving one or more varied collections, see gufo:standsInQualifiedParthood.

isSubQuantityOf
type: ObjectProperty
sub property of: isObjectProperPartOf
type: TransitiveProperty
domain: Quantity
range: Quantity
comment: Identifies a gufo:Quantity of which the quantity is a part. For example, the quantity of water in a wine glass is a sub-quantity of the wine in that glass. gufo:isSubQuantityOf is transitive (Guizzardi, 2005, p. 184). Sub-quantities are always essential parts of their wholes. Thus, gufo:standsInQualifiedParthood is not applicable for sub-quantities.

manifestedIn
type: ObjectProperty
domain: Aspect
range: Event
comment: Identifies a gufo:Event in which the gufo:Aspect is manifested. For example, the passing of an electrical current in a conductor is an event that encompasses the manifestation of an aspect inhering in a copper wire (the wire's electrical conductivity).

mediates
type: ObjectProperty
type: AsymmetricProperty
type: IrreflexiveProperty
domain: Relator
range: Endurant
comment: Identifies the endurants mediated by a gufo:Relator. For example, John and Mary's marriage mediates John and Mary.

participatedIn
type: ObjectProperty
domain: Object
range: Event
comment: Identifies a gufo:Event in which the gufo:Object participated. Examples include the participation of Freddy Mercury in Queen's Live Aid Concert and the participation of an airplane in a flight.

partitions
type: ObjectProperty
sub property of: categorizes
domain: Class
  intersection of: Type
  intersection of: Class
    complement of: AbstractIndividualType
  intersection of: Class
    complement of: ConcreteIndividualType
comment: Identifies a gufo:Type whose instances are classified by exactly one instance of the partitioning higher-order type. For example, "AnimalSpecies" gufo:partitions "Animal". Instances of "AnimalSpecies" such as "Lion", "Hiena" must be disjoint subclasses of "Animal". OWL 2 punning should be used to capture the two facets of "Lion" and "Hiena" in this example: (i) as instances of "AnimalSpecies", and (ii) as subclasses of "Animal". Note that the partitioned type (in the example "Animal") may or may not be declared to be a disjoint union of the explicitly enumerated subclasses (such as "Lion", "Hiena"). This is because other instances of the higher-order type ("AnimalSpecies") may exist that are not explicitly enumerated in the ontology. The partitioned type is termed the "base type" in the "powertype pattern" see Carvalho et al (2017), the higher-order type is often called the "powertype". For further details and formalization of "partitioning", see Carvalho et al (2017) which combines UFO with MLT (a multi-level modeling theory). V. A. Carvalho, J. P. A. Almeida, C. M. Fonseca, and G. Guizzardi, “Multi-level ontology-based conceptual modeling,” Data & Knowledge Engineering, vol. 109, p. 3–24, 2017. <http://dx.doi.org/10.1016/j.datak.2017.03.002>

standsIn
type: ObjectProperty
domain: Thing
range: Situation
comment: Identifies a gufo:Situation in which the entity stands. This implementation includes sub-properties of gufo:standsIn to identify situations concerning the attribution of (mutable) values to qualities, variable relationships, the instantiation of non-contingent types, temporary parthood and temporary constitution.

standsInQualifiedAttribution
type: ObjectProperty
sub property of: standsIn
domain: Endurant
range: QualityValueAttributionSituation
comment: Identifies a gufo:QualityValueAttributionSituation in which the endurant stands. The identified gufo:QualityValueAttributionSituation is then used with the gufo:concernsQualityValue data property or the gufo:concernsReifiedQualityValue object property to indicate a quality value attributed to the gufo:Endurant standing in the situation. This forms a pattern to represent that quality values may differ in different situations.

standsInQualifiedConstitution
type: ObjectProperty
sub property of: standsIn
domain: Endurant
range: TemporaryConstitutionSituation
comment: Identifies a gufo:TemporaryConstitutionSituation in which an endurant stands temporarily (as a constituent). The identified gufo:TemporaryConstitutionSituation is further related with an endurant (the whole) through the gufo:concernsConstitutedEndurant object property. This forms a pattern to represent temporary constitution, in which the relationships between constituents and constituted endurant vary in different situations. Consider, for example, a group of people (understood as a gufo:FixedCollection) constituting a band (understood as a gufo:FunctionalComplex). In this case, any change in the membership of the group (e.g., the replacement of one person) creates a different group of people. Therefore, the band's constitution can change in time, and the pattern using gufo:TemporaryConstitutionSituation is applicable.

standsInQualifiedInstantiation
type: ObjectProperty
sub property of: standsIn
domain: Endurant
range: TemporaryInstantiationSituation
comment: Identifies a gufo:TemporaryInstantiationSituation in which the endurant stands. The identified gufo:TemporaryInstantiationSituation is further related with a gufo:NonRigidType through the gufo:concernsNonRigidType object property. This forms a pattern to represent the contigent instantiation of a non-rigid type by the endurant, in which case instantiation may vary in different situations.

standsInQualifiedParthood
type: ObjectProperty
sub property of: standsIn
domain: Endurant
range: TemporaryParthoodSituation
comment: Identifies a gufo:TemporaryParthoodSituation in which the endurant stands (as a temporary part). The identified gufo:TemporaryParthoodSituation is further related with an endurant (the whole) through the gufo:concernsTemporaryWhole object property. This forms a pattern to represent temporary parthood, in which the relationships between parts and wholes vary in different situations. In particular, this pattern is useful in case parts may be separated from their wholes, attached to other wholes, replaced.

standsInQualifiedRelationship
type: ObjectProperty
sub property of: standsIn
domain: Endurant
range: TemporaryRelationshipSituation
comment: Identifies a gufo:TemporaryRelationshipSituation in which the endurant stands. The identified gufo:TemporaryRelationshipSituation is then used with the gufo:concernsRelatedEndurant and the gufo:concernsRelationshipType object properties to indicate the related element and the type of relationship that applies. This forms a pattern to represent that relationships that may change in different situations. For example, "heavierThan" may change when the objects involved gain or lose weight. For material relations, prefer the use of gufo:Relator.

wasCreatedIn
type: ObjectProperty
domain: Endurant
range: Event
comment: Identifies the gufo:Event which brought the gufo:Endurant into existence. For example, a musical piece is created in an act of composition (or in an event that is part of it), a piece of legislation is created in a complex legislative process. Benevides et al. (2019) only discussed creation of objects; gufo:wasCreatedIn is extended to endurants in general. Further, in that work "createdBy" required the event to "bring about" a situation in which the created object is present. We relax this requirement here, such that the object may be created and terminated in the scope of the identified gufo:Event. A. B. Benevides, J. R. Bourguet, G. Guizzardi, R. Penãloza, and J. P. A. Almeida, “Representing a reference foundational ontology of events in SROIQ,” Applied ontology, vol. 14, iss. 3, p. 293–334, 2019. <http://dx.doi.org/10.3233/AO-190214>

wasTerminatedIn
type: ObjectProperty
domain: Endurant
range: Event
comment: Identifies the gufo:Event in which the gufo:Endurant was brought to an end. For example, the Space Shuttle Challenger (OV-099) (a gufo:FunctionalComplex) was destroyed during the launch of its tenth flight (a gufo:Event). Benevides et al. (2019) only discussed termination of objects; gufo:wasCreatedIn is extended to endurants in general. This means that a gufo:Relator (such as a marriage) can be declared terminated. Further, in that work "terminatedBy" required the event to be "triggered" by a situation in which the terminated object is present. We relax this requirement here, such that the object may be created and terminated in the scope of the identified gufo:Event. A. B. Benevides, J. R. Bourguet, G. Guizzardi, R. Penãloza, and J. P. A. Almeida, “Representing a reference foundational ontology of events in SROIQ,” Applied ontology, vol. 14, iss. 3, p. 293–334, 2019. <http://dx.doi.org/10.3233/AO-190214>

account key
type: ObjectProperty
domain: Online Account
range: Cryptographic Key
definition: Relates an online account to the cryptographic key that identifies it — the seam joining a decentralized-identity account (e.g. a Nostr account's nostrPubkey literal) to the key as a first-class entity.

address holder
type: ObjectProperty
type: FunctionalProperty
domain: Address Tenure
range: Agent
definition: The agent who held the contact point over the tenure's interval.

bcc
type: ObjectProperty
domain: Email Message
range: Email Address
definition: A blind-carbon-copy recipient address of a message (RFC 5322 Bcc).

cc
type: ObjectProperty
domain: Email Message
range: Email Address
definition: A carbon-copy recipient address of a message (RFC 5322 Cc).

certified identity
type: ObjectProperty
type: FunctionalProperty
domain: Certification
range: Agent
definition: The agent identity a certification binds the key to.

certified key
type: ObjectProperty
type: FunctionalProperty
domain: Certification
range: Cryptographic Key
definition: The cryptographic key a certification vouches for.

certifier
type: ObjectProperty
type: FunctionalProperty
domain: Certification
range: Agent
definition: The agent that made a certification.

cites source
type: ObjectProperty
type: FunctionalProperty
domain: Citation
range: Source
definition: Relates a citation to the source it points into.

contained in place
type: ObjectProperty
type: TransitiveProperty
domain: Place
range: Place
definition: Relates a place to a larger place that geographically contains it; transitive.

delivers to account
type: ObjectProperty
domain: Email Address
range: Online Account
definition: Relates an email address to the online account it delivers to — the seam joining an address (held by an agent) to the account a message resides in.

developer
type: ObjectProperty
domain: Software Project
range: Agent
definition: Relates a software project to an agent that develops it.

during interval
type: ObjectProperty
domain: Time-Scoped Relation
range: Time Interval
definition: Relates a time-scoped relation to the interval over which it holds.

endorses
type: ObjectProperty
domain: Agent
range: Agent
definition: A convenience shortcut recording that one agent vouches for another. Deliberately NOT symmetric (endorsement is directional) and NOT transitive (trust must not propagate inside the reasoner — that is the metric the perspectival TrustAssertion bounds). Use gmeow:TrustAssertion for leveled, dated, perspectival trust.

event place
type: ObjectProperty
domain: Life Event
range: Place
definition: The place at which a life event occurred.

from
type: ObjectProperty
domain: Email Message
range: Email Address
definition: The author address of a message (RFC 5322 From).

has agreement
type: ObjectProperty
domain: Agent
range: Agreement
definition: Relates an agent to an agreement it is party to. The party-ship period is carried with gmeow:validFrom/validUntil on this statement; the agreement's own term/effective dates live on the gmeow:Agreement individual (no double-modelling).

has attachment
type: ObjectProperty
sub property of: has body part
domain: Message
range: Attachment
definition: Relates a message to one of its attachments.

has authentication result
type: ObjectProperty
domain: Message
range: Authentication Result
definition: Relates a message to an authentication check performed on it.

has author
type: ObjectProperty
domain: Creative Work
range: Agent
definition: Relates a creative work to an agent chiefly responsible for creating its intellectual content.

has body part
type: ObjectProperty
domain: Message
range: Body Part
definition: Relates a message to a MIME part of its body.

has child
type: ObjectProperty
inverse of: has parent
domain: Person
range: Person
definition: Relates a person to a child; the inverse of hasParent.

has contact point
type: ObjectProperty
domain: Agent
range: Contact Point
definition: Relates an agent to a means of contacting it.

has coordinates
type: ObjectProperty
domain: Place
range: Geo Coordinates
definition: Relates a place to its geographic coordinates.

has father
type: ObjectProperty
sub property of: has parent
domain: Person
range: Person
definition: Relates a person to a male parent.

has header
type: ObjectProperty
domain: Message
range: Message Header
definition: Relates a message to one of its RFC 5322 headers.

has keyword
type: ObjectProperty
domain: Message
range: Message Keyword
definition: Relates a message to a flag/keyword applied to it.

has member
type: ObjectProperty
inverse of: member of
domain: Organization
range: Agent
definition: Relates an organization to one of its member agents; the inverse of memberOf.

has met
type: ObjectProperty
type: SymmetricProperty
domain: Agent
range: Agent
definition: Records that two agents have met; symmetric. The occasion/period is carried with gmeow:validFrom/validUntil on the statement.

has mother
type: ObjectProperty
sub property of: has parent
domain: Person
range: Person
definition: Relates a person to a female parent.

has name
type: ObjectProperty
domain: Person
range: Person Name
definition: Relates a person to a structured, typed name they bear.

has occupation
type: ObjectProperty
domain: Person
range: Occupation
definition: Relates a person to an occupation they hold or have held.

has officiant
type: ObjectProperty
sub property of: has participant
domain: Life Event
range: Person
definition: A person who officiated at a life event.

has parent
type: ObjectProperty
domain: Person
range: Person
definition: Relates a person to a parent (any kind: biological, adoptive, step, or foster).

has participant
type: ObjectProperty
domain: Life Event
range: Agent
definition: An agent that took part in a life event.

has partner
type: ObjectProperty
domain: Couple Relationship
range: Person
definition: Relates a couple relationship to one of its two partners.

has party
type: ObjectProperty
domain: Agreement
range: Agent
definition: Relates an agreement to an agent that is bound by it.

has principal
type: ObjectProperty
sub property of: has participant
domain: Life Event
range: Person
definition: The person a life event is principally about (e.g. the child in a Birth, the deceased in a Death).

has relay hop
type: ObjectProperty
domain: Message
range: Relay Hop
definition: Relates a message to a hop in its delivery path.

has repository
type: ObjectProperty
domain: Software Project
range: Repository
definition: Relates a software project to a source-code repository.

has role
type: ObjectProperty
domain: Membership
range: Role
definition: Relates a membership to the role the member plays.

has sibling
type: ObjectProperty
type: SymmetricProperty
domain: Person
range: Person
definition: Relates a person to a sibling; symmetric.

has signature
type: ObjectProperty
domain: Message
range: Cryptographic Signature
definition: Relates a message to a cryptographic signature over it.

has skill
type: ObjectProperty
domain: Agent
range: Skill
definition: Relates an agent to a skill it possesses.

has source
type: ObjectProperty
domain: Entity
range: Source
definition: Relates an entity or reified claim to a source that provides evidence for it. The strength of that evidence is recorded with gmeow:confidence on the supported statement.

has spouse
type: ObjectProperty
type: SymmetricProperty
domain: Person
range: Person
definition: Relates a person to a spouse; symmetric.

has used
type: ObjectProperty
domain: Agent
range: Entity
definition: Records that an agent has used some entity (a tool, service, or work). The period is carried with gmeow:validFrom/validUntil on the statement.

has witness
type: ObjectProperty
sub property of: has participant
domain: Life Event
range: Person
definition: A person who witnessed a life event.

has worked with
type: ObjectProperty
type: SymmetricProperty
domain: Agent
range: Agent
definition: Records that two agents have worked together; symmetric. The period is carried with gmeow:validFrom/validUntil on the statement, or reified as a gmeow:ProfessionalRelationship.

holds account
type: ObjectProperty
domain: Agent
range: Online Account
definition: Relates an agent to an online account it holds.

holds key
type: ObjectProperty
domain: Agent
range: Cryptographic Key
definition: Relates an agent to a cryptographic key it holds. The period over which the agent held the key may be carried with gmeow:validFrom/validUntil on this statement.

in reply to
type: ObjectProperty
domain: Message
range: Message
definition: Relates a message to the message it directly replies to (RFC 5322 In-Reply-To).

key scheme
type: ObjectProperty
type: FunctionalProperty
domain: Cryptographic Key
range: Key Scheme
definition: The scheme/format of a cryptographic key (one of the gmeow:KeyScheme individuals). Functional: a key has exactly one scheme — a key of a different scheme is a different key.

mailbox of account
type: ObjectProperty
type: FunctionalProperty
domain: Mailbox
range: Online Account
definition: Relates a mailbox to the online account that holds it.

member of
type: ObjectProperty
domain: Agent
range: Organization
definition: Relates an agent to an organization it belongs to.

part of thread
type: ObjectProperty
domain: Message
range: Thread
definition: Relates a message to the thread (conversation) it belongs to.

references
type: ObjectProperty
domain: Message
range: Message
definition: Relates a message to an earlier message in its reference chain (RFC 5322 References).

relationship child
type: ObjectProperty
type: FunctionalProperty
domain: Parent-Child Relationship
range: Person
definition: The child in a reified parent-child relationship.

relationship interval
type: ObjectProperty
domain: Interpersonal Relationship
range: Time Interval
definition: The time interval over which an interpersonal relationship held. (A relator carries its period this way rather than via duringInterval, which is reserved for gufo:Situation-based time-scoped relations.)

relationship parent
type: ObjectProperty
type: FunctionalProperty
domain: Parent-Child Relationship
range: Person
definition: The parent in a reified parent-child relationship.

relationship party
type: ObjectProperty
domain: Interpersonal Relationship
range: Agent
definition: An agent who is one of the parties to an interpersonal relationship. Non-functional: a relationship typically binds two parties (and is left open for group ties).

reply to
type: ObjectProperty
domain: Email Message
range: Email Address
definition: An address to which replies should be sent (RFC 5322 Reply-To).

residence mailbox
type: ObjectProperty
type: FunctionalProperty
domain: Mailbox Residence
range: Mailbox
definition: The mailbox a mailbox-residence concerns.

resident message
type: ObjectProperty
type: FunctionalProperty
domain: Mailbox Residence
range: Message
definition: The message a mailbox-residence concerns.

resides in
type: ObjectProperty
domain: Message
range: Mailbox
definition: Relates a message to a mailbox/label it currently resides in. Time-varying residence is reified as gmeow:MailboxResidence; on this convenience property the period may be carried with gmeow:validFrom/validUntil.

sender
type: ObjectProperty
domain: Email Message
range: Email Address
definition: The transmitting address of a message, where different from the author (RFC 5322 Sender).

signed by
type: ObjectProperty
domain: Cryptographic Signature
range: Agent
definition: The agent (or signing identity) that produced a signature.

signing key
type: ObjectProperty
type: FunctionalProperty
domain: Cryptographic Signature
range: Cryptographic Key
definition: The cryptographic key that produced a signature (the trust module's CryptographicKey). Complements gmeow:signedBy: signedBy gives the identity, signingKey gives the key — the pair a gmeow:Certification attests.

tenured contact point
type: ObjectProperty
type: FunctionalProperty
domain: Address Tenure
range: Contact Point
definition: The contact point an address-tenure concerns.

to
type: ObjectProperty
domain: Email Message
range: Email Address
definition: A primary recipient address of a message (RFC 5322 To).

trustee
type: ObjectProperty
type: FunctionalProperty
domain: Trust Assertion
range: Agent
definition: The agent that is trusted by the trustor in a trust-assertion.

trustor
type: ObjectProperty
type: FunctionalProperty
domain: Trust Assertion
range: Agent
definition: The agent whose (subjective) trust a trust-assertion expresses — the perspective holder.

was attributed to
type: ObjectProperty
domain: Entity
range: Agent
definition: Ascribes responsibility for an entity to an agent.

was derived from
type: ObjectProperty
domain: Entity
range: Entity
definition: Relates a derived entity to the entity it was derived from — e.g. a text extraction, summary, or embedding to its source. The derivation's confidence and generating agent are recorded with gmeow:confidence and gmeow:wasGeneratedBy.

was generated by
type: ObjectProperty
domain: Entity
range: Activity
definition: Relates an entity to the activity that produced it.

concernsQualityValue
type: DatatypeProperty
domain: QualityValueAttributionSituation
comment: Determines a quality value associated with the gufo:ConcreteIndividual that stands in the gufo:QualityValueAttributionSituation. Use gufo:concernsReifiedQualityValue instead when quality values are refied. It is recommended that subproperties of gufo:concernsQualityValue are created, possibly identifying the datatype to be used. For example, "concernsTemperatureValue" could be defined as a sub-property of gufo:concernsQualityValue with range xsd:double.

hasBeginPointInXSDDate
type: DatatypeProperty
type: FunctionalProperty
domain: ConcreteIndividual
range: date
comment: Determines the begin point for a gufo:ConcreteIndividual, using a xsd:date literal. In the case of endurants, gufo:asBeginPointInXSDDate determines the time point when the endurant comes into existence. In the case of events, this data property determines the time point when the event starts to take place. In the case of situation, it determines the time point when the situation begins to hold. Use gufo:hasBeginPoint instead when temporal entities are reified.

hasBeginPointInXSDDateTimeStamp
type: DatatypeProperty
type: FunctionalProperty
domain: ConcreteIndividual
range: dateTimeStamp
comment: Determines the begin point for a gufo:ConcreteIndividual, using a xsd:dateTimeStamp literal. In the case of endurants, gufo:hasBeginPointInXSDDateTimeStamp determines the time point when the endurant comes into existence. In the case of events, this data property determines the time point when the event starts to take place. In the case of situation, it determines the time point when the situation begins to hold. Use gufo:hasBeginPoint instead when temporal entities are reified.

hasEndPointInXSDDate
type: DatatypeProperty
type: FunctionalProperty
domain: ConcreteIndividual
range: date
comment: Determines the end point for a gufo:ConcreteIndividual using a xsd:date literal. In the case of endurants, gufo:hasEndPointInXSDDate determines the time point when the endurant ceases to exist. In the case of events, this data property determines the time point when the event ends. In the case of situation, it determines the time point when the situation ceases to hold. Use gufo:hasEndPoint instead when temporal entities are reified.

hasEndPointInXSDDateTimeStamp
type: DatatypeProperty
type: FunctionalProperty
domain: ConcreteIndividual
range: dateTimeStamp
comment: Determines the end point for a gufo:ConcreteIndividual using a xsd:dateTimeStamp literal. In the case of endurants, gufo:hasEndPointInXSDDateTimeStamp determines the time point when the endurant ceases to exist. In the case of events, this data property determines the time point when the event ends. In the case of situation, it determines the time point when the situation ceases to hold. Use gufo:hasEndPoint instead when temporal entities are reified.

hasQualityValue
type: DatatypeProperty
domain: ConcreteIndividual
comment: Determines a quality value associated with the concrete individual. Use gufo:hasReifiedQualityValue instead when quality values are reified. It is recommended that subproperties of gufo:hasQualityValue are created, possibly identifying the datatype to be used. For example, "hasTemperatureValue" could be defined as a sub-property of gufo:hasQualityValue whose domain is "Temperature" (specializing gufo:Quality) and whose range is xsd:double.

hasValueComponent
type: DatatypeProperty
domain: QualityValue
comment: This property is used for quality values that are defined in terms of a multidimensional quality structure (such as color conceived in terms of hue, saturation and brightness). Each value component of a quality value (a particular value for hue, a particular value for saturation, a particular value for brightness) is determined with this property. It is recommended that subproperties of gufo:hasValueComponent are created to indicate values for particular dimensions, possibly identifying the datatype to be used. For example "hasHueComponent", "hasSaturationComponent" and "hasBrightnessComponent" could be used as data properties specializing gufo:hasValueComponent with the xsd:double datatype.

account name
type: DatatypeProperty
domain: Online Account
range: Literal
definition: The handle or user name identifying the account on its service.

ActivityPub actor
type: DatatypeProperty
domain: Online Account
range: anyURI
definition: The ActivityPub actor IRI of a federated-social account.

at time
type: DatatypeProperty
range: dateTime
definition: The instant at which a point-like event or observation occurred.

authentication method
type: DatatypeProperty
type: FunctionalProperty
domain: Authentication Result
range: Literal
definition: The authentication method checked: dkim, spf, dmarc, arc, iprev, or auth.

authentication result
type: DatatypeProperty
type: FunctionalProperty
domain: Authentication Result
range: Literal
definition: The verdict of an authentication check: pass, fail, none, softfail, neutral, temperror, or permerror.

authentication server
type: DatatypeProperty
type: FunctionalProperty
domain: Authentication Result
range: Literal
definition: The authentication-serv-id (authserv-id) that performed the check.

certification level
type: DatatypeProperty
type: FunctionalProperty
domain: Certification
range: Literal
definition: How carefully the binding was verified (OpenPGP certification level): generic, persona, casual, or positive.

date published
type: DatatypeProperty
domain: Creative Work
range: dateTime
definition: The date a creative work was published or issued.

email
type: DatatypeProperty
domain: Agent
range: Literal
definition: An email address at which an agent can be reached.

ended at time
type: DatatypeProperty
type: FunctionalProperty
domain: Time Interval
range: dateTime
definition: The instant at which a time interval ends; absent if the interval is still open.

event date
type: DatatypeProperty
domain: Life Event
range: Literal
definition: The date (possibly approximate or partial) on which a life event occurred.

family name
type: DatatypeProperty
domain: Person
range: Literal
definition: A person's family (last) name.

filename
type: DatatypeProperty
type: FunctionalProperty
domain: Attachment
range: Literal
definition: The filename of an attachment.

fingerprint
type: DatatypeProperty
domain: Cryptographic Key
range: Literal
definition: A fingerprint (hash) identifying a key. Not functional: different sources may report differing or differently-formatted fingerprints for the same key.

given name
type: DatatypeProperty
domain: Person
range: Literal
definition: A person's given (first) name.

given name part
type: DatatypeProperty
domain: Person Name
range: Literal
definition: A given (fore) name part within a structured name.

header name
type: DatatypeProperty
type: FunctionalProperty
domain: Message Header
range: Literal
definition: The field name of a message header.

header value
type: DatatypeProperty
type: FunctionalProperty
domain: Message Header
range: Literal
definition: The field value of a message header.

hop ordinal
type: DatatypeProperty
type: FunctionalProperty
domain: Relay Hop
range: integer
definition: The position of a hop within the message path (1 = closest to the origin).

identifier
type: DatatypeProperty
domain: Creative Work
range: Literal
definition: A formal identifier of a creative work, such as a DOI or patent number.

introducer amount
type: DatatypeProperty
type: FunctionalProperty
domain: Trust Assertion
range: integer
definition: The trust-signature amount/weight the trustor assigns to the trustee as an introducer.

introducer depth
type: DatatypeProperty
type: FunctionalProperty
domain: Trust Assertion
range: integer
definition: The trust-signature depth: how many levels of indirect introducers the trustor is willing to follow (a trust-signature notion, not computed here).

key algorithm
type: DatatypeProperty
domain: Cryptographic Key
range: Literal
definition: The key's algorithm (e.g. rsa, ed25519, secp256k1). Not functional (source-variable).

key expires at
type: DatatypeProperty
domain: Cryptographic Key
range: dateTime
definition: The instant a key is set to expire. Not functional (sources may report different expiry, and subkeys differ).

key id
type: DatatypeProperty
domain: Cryptographic Key
range: Literal
definition: A short identifier for a key (e.g. a PGP long key id). Not functional (source-variable).

key material
type: DatatypeProperty
domain: Cryptographic Key
range: Literal
definition: The public key material itself (armored or hex form). Not functional (encodings vary by source).

latitude
type: DatatypeProperty
domain: Geo Coordinates
range: decimal
definition: The latitude of a geographic point in decimal degrees.

list id
type: DatatypeProperty
domain: Message
range: Literal
definition: The mailing-list identifier a message was distributed through (RFC 2919 List-Id).

longitude
type: DatatypeProperty
domain: Geo Coordinates
range: decimal
definition: The longitude of a geographic point in decimal degrees.

mailbox name
type: DatatypeProperty
domain: Mailbox
range: Literal
definition: The display name of a mailbox or label.

mailbox role
type: DatatypeProperty
type: FunctionalProperty
domain: Mailbox
range: Literal
definition: The special-use role of a mailbox (JMAP role): inbox, archive, drafts, sent, trash, junk, templates.

media type
type: DatatypeProperty
type: FunctionalProperty
domain: Body Part
range: Literal
definition: The MIME media type of a body part (e.g. text/plain, application/pdf).

name
type: DatatypeProperty
domain: Entity
range: Literal
definition: The name by which an entity is known.

name type
type: DatatypeProperty
type: FunctionalProperty
domain: Person Name
range: Literal
definition: The kind of name (e.g. birth name, married name, also-known-as, religious name).

NIP-05 identifier
type: DatatypeProperty
domain: Online Account
range: Literal
definition: A Nostr NIP-05 identifier (user@domain) verifying a Nostr account against a domain.

Nostr public key
type: DatatypeProperty
domain: Online Account
range: Literal
definition: The Nostr public key (npub / hex) identifying a decentralized-identity account.

preview
type: DatatypeProperty
domain: Message
range: Literal
definition: A short plain-text preview/snippet of a message's body.

programming language
type: DatatypeProperty
domain: Software Project
range: Literal
definition: A programming language a software project is written in.

received at
type: DatatypeProperty
domain: Message
range: dateTime
definition: When a message was received by the storing system (JMAP receivedAt / Gmail internalDate).

relay at
type: DatatypeProperty
type: FunctionalProperty
domain: Relay Hop
range: dateTime
definition: The server timestamp recorded for a relay hop.

relay by
type: DatatypeProperty
type: FunctionalProperty
domain: Relay Hop
range: Literal
definition: The server that performed a relay hop.

relay from
type: DatatypeProperty
type: FunctionalProperty
domain: Relay Hop
range: Literal
definition: The host a relay hop received the message from.

relay protocol
type: DatatypeProperty
type: FunctionalProperty
domain: Relay Hop
range: Literal
definition: The protocol used for a relay hop (e.g. ESMTP, ESMTPS).

RFC message id
type: DatatypeProperty
type: FunctionalProperty
domain: Message
range: Literal
definition: The RFC 5322 Message-ID of a message.

sent at
type: DatatypeProperty
domain: Message
range: dateTime
definition: When a message was sent (RFC 5322 Date).

sex
type: DatatypeProperty
domain: Person
range: Literal
definition: The recorded sex of a person (e.g. male, female, intersex, unknown).

signature algorithm
type: DatatypeProperty
type: FunctionalProperty
domain: Cryptographic Signature
range: Literal
definition: The algorithm used for a signature (e.g. rsa-sha256, ed25519).

signing domain
type: DatatypeProperty
type: FunctionalProperty
domain: Cryptographic Signature
range: Literal
definition: The domain asserted by a signature (e.g. the DKIM d= tag).

size estimate
type: DatatypeProperty
domain: Message
range: integer
definition: The estimated size of a message in octets.

started at time
type: DatatypeProperty
type: FunctionalProperty
domain: Time Interval
range: dateTime
definition: The instant at which a time interval begins.

subject
type: DatatypeProperty
domain: Message
range: Literal
definition: The subject line of a message (RFC 5322 Subject).

surname part
type: DatatypeProperty
domain: Person Name
range: Literal
definition: A surname (family) name part within a structured name.

telephone
type: DatatypeProperty
domain: Agent
range: Literal
definition: A telephone number at which an agent can be reached.

title
type: DatatypeProperty
domain: Creative Work
range: Literal
definition: The title of a creative work.

trust level
type: DatatypeProperty
type: FunctionalProperty
domain: Trust Assertion
range: Literal
definition: The degree of owner-trust expressed: ultimate, full, marginal, or none.

verification status
type: DatatypeProperty
type: FunctionalProperty
domain: Cryptographic Signature
range: Literal
definition: The verification outcome of a signature: verified, failed, or unverified.

AbstractIndividual
type: Class
subclass of: Individual
disjoint with: ConcreteIndividual
comment: A gufo:Individual that does not exist in space-time in the same way as a gufo:ConcreteIndividual does. A gufo:AbstractIndividual has no spatiotemporal qualities in its own right. Hence, it does not make sense to ask how much space it now occupies (Gideon, 2018) and when it was created or destroyed. Examples include the number ten, the null set, and the proposition that 'Obama was the president of the United States'. Rosen, Gideon, "Abstract Objects", The Stanford Encyclopedia of Philosophy (Winter 2018 Edition), Edward N. Zalta (ed.), <https://plato.stanford.edu/archives/win2018/entries/abstract-objects/>

AbstractIndividualType
type: Class
subclass of: Type
disjoint with: ConcreteIndividualType
disjoint with: RelationshipType
comment: A gufo:Type whose instances are abstract individuals. Instances of gufo:AbstractIndividualType are subclasses of gufo:AbstractIndividual. Examples include the types "NaturalNumber", "Set", "Proposition".

AntiRigidType
type: Class
subclass of: NonRigidType
disjoint with: SemiRigidType
comment: A gufo:NonRigidType that applies contingently to all its instances (see Guizzardi, 2005, chapter 4). Examples include the gufo:Phase "Child", the gufo:PhaseMixin "InfantAnimal", the gufo:Role "Student", and the gufo:RoleMixin "Customer".

Aspect
type: Class
subclass of: Endurant
disjoint with: Object
disjoint union of: ExtrinsicAspect
disjoint union of: IntrinsicAspect
comment: A gufo:Endurant that depends on at least one other concrete individual for its existence. A gufo:Aspect is a characteristic or trait of a concrete individual that is itself conceived as an individual. Examples include: intrinsic physical aspects, such as the Moon's mass, Lassie's fur color; mental dispositions, such as Bob's math skills, his belief that the number one is odd; as well as relational aspects, such as John's love for Mary and the marriage between John and Mary. The specific sort of existential dependence connecting aspects to their bearers is called inherence. Corresponds to "Moment" in Guizzardi (2005). Also termed "property instance", "particularized property", "individual accident", or "(variable) trope" in the philosophical literature.

Category
type: Class
subclass of: NonSortal
subclass of: RigidType
comment: A gufo:EndurantType that is both non-sortal and rigid. It captures essential properties that apply to instances of different kinds. For example, "PhysicalObject" may be considered a gufo:Category, encompassing objects such as cars, planets, trees. "Agent" may be a gufo:Category that classifies both people and organizations.

Collection
type: Class
subclass of: Object
disjoint union of: FixedCollection
disjoint union of: VariableCollection
comment: A complex gufo:Object whose parts (the members of the collection) have a uniform structure (i.e., members are conceived as playing the same role in the collection). Collections may have a fixed or variable membership, which can be asserted using gufo:FixedCollection and gufo:VariableCollection respectively. Examples include a deck of cards, a pile of bricks, a forest (conceived as a collection of trees), and a group of people. Collections in many cases constitute a functional complex. For example, a pile of bricks may constitute a wall, a group of people may constitute a football team. A gufo:Collection may be decomposed into "smaller" collections. For instance, a group of people may be decomposed into a group of English speakers and a group of Italian speakers. Sub collections may or may not share members among them.

ComparativeRelationshipType
type: Class
subclass of: RelationshipType
disjoint with: MaterialRelationshipType
comment: A gufo:RelationshipType derived from intrinsic aspects of the related entities. For example, "heavierThan", "olderThan". For a gufo:ComparativeRelationshipType it is recommended to identify the types of intrinsic aspects from which it is derived (see gufo:isDerivedFrom). For example "heavierThan" is derived from the "Weight" quality type. Note that, in the case of relationships that may change in different circumstances or times, the use of a qualified relation pattern enables indicating the period of time in which the relationship holds. See gufo:TemporaryRelationshipSituation. Corresponds to "comparative formal relation" in Guizzardi (2005) and "Comparative Relation" in Fonseca et al. (2019).

ConcreteIndividual
type: Class
subclass of: Individual
disjoint union of: Endurant
disjoint union of: Event
disjoint union of: Situation
comment: A gufo:Individual that exists in space-time. Concrete individuals comprise not only object-like entities (a car, a mountain, a person, a marriage, a belief), but also events (a business meeting, a soccer match) and situations (the situation in which a person weighs 80 kilograms, the situation in which a bank account is overdrawn).

ConcreteIndividualType
type: Class
subclass of: Type
disjoint with: RelationshipType
comment: A gufo:Type whose instances are concrete individuals. Instances of gufo:ConcreteIndividualType are subclasses of gufo:ConcreteIndividual. Examples include the gufo:Kind "Person", the gufo:Category "Physical Object", the gufo:EventType "Business Meeting".

Endurant
type: Class
subclass of: ConcreteIndividual
disjoint union of: Aspect
disjoint union of: Object
comment: A gufo:ConcreteIndividual that endures in time and may change qualitatively while keeping its identity. Examples include: ordinary objects of everyday experience, such as a person, a house, and a car; reified relationships, such as a marriage, a rental contract, and a person's love for another; and existentially-dependent aspects of objects, such as a car's weight, a person's language skills, and a house's color. Also termed "continuant" in the philosophical literature.

EndurantType
type: Class
subclass of: ConcreteIndividualType
disjoint with: EventType
disjoint with: SituationType
disjoint union of: NonRigidType
disjoint union of: RigidType
disjoint union of: NonSortal
disjoint union of: Sortal
comment: A gufo:Type whose instances are endurants. Instances of gufo:EndurantType are subclasses of gufo:Endurant. Examples include the object kind "Person", the phase "Child", the relator kind "Marriage". See Guizzardi et al. (2018) for details concerning the taxonomy of endurant types included here.

Event
type: Class
subclass of: ConcreteIndividual
comment: A gufo:ConcreteIndividual that 'occurs' or 'happens' in time. They may be instantaneous or long-running. Events are those "things that happen to or are performed by" (Casati and Varzi, 2015) endurants. Examples include actions and processes, such as a business meeting, a communicative act, a soccer match, a goal kick, the clicking of a mouse button; as well as natural occurrences such as an earthquake, the fall of the meteor that caused the extinction of the dinosaurs. Also termed "happening", "occurrence", "perdurant" or "occurrent" in the philosophical literature. Casati, R. & Varzi, A. (2015). Events. In E.N. Zalta (Ed.), The Stanford Encyclopedia of Philosophy (Winter 2015 ed.). 19 Metaphysics Research Lab, Stanford University. https://plato.stanford.edu/archives/win2015/entries/events/

EventType
type: Class
subclass of: ConcreteIndividualType
disjoint with: SituationType
comment: A gufo:Type whose instances are events. Instances of gufo:EventType are subclasses of gufo:Event. Examples include "Business Meeting", "Birth", "Musical Performance".

ExtrinsicAspect
type: Class
subclass of: Aspect
disjoint with: IntrinsicAspect
disjoint union of: ExtrinsicMode
disjoint union of: Relator
comment: A gufo:Aspect that depends on one or more concrete individuals. Extrinsic (or "relational") aspects are reified relationships, e.g., John and Mary's marriage, Mary's employment contract at Nasa, or parts of those relationships, e.g., John's obligations towards Mary in the scope of the marriage, Mary's reciprocal claims, Mary's obligations towards John, John's reciprocal claims. Extrinsic aspects can also be reified one-sided relationships, e.g., John's admiration for Obama (which depends on Obama but does not characterize him). Corresponds to "Extrinsic Moment" in Fonseca et al (2019). Encompasses "Externally Depedent Mode", "Qua Individual" and "Relator" in Guizzardi (2005).

ExtrinsicMode
type: Class
subclass of: ExtrinsicAspect
subclass of: Restriction
  on property: externallyDependsOn
  some values from: ConcreteIndividual
subclass of: Restriction
  on property: inheresIn
  qualified cardinality: 1
  on class: ConcreteIndividual
disjoint with: Relator
comment: A gufo:ExtrinsicAspect that inheres in a concrete individual and depends on others for its existence. A gufo:ExtrinsicMode can be understood as a reified one-sided relationship, such as John's admiration for Mary. Corresponds to "Extrinsic Moment" in Fonseca et al (2019). Encompasses what "Externally Dependent Mode", "Qua Individual" and "Relator" in Guizzardi (2005).

FixedCollection
type: Class
subclass of: Collection
disjoint with: VariableCollection
comment: A gufo:Collection for which no change in membership is possible. Such a collection obeys an extensional principle of identity, i.e., two fixed collections are the same if, and only if, they have the same members. Consider, for example, a group of people understood as a gufo:FixedCollection. In this case, any change in the membership of the group (e.g., the addition of one person) would in fact create a different group of people. In this case, the gufo:FixedCollection may be contrasted with the complexes they constitute. For instance, The Beatles (the band conceived as a gufo:FunctionalComplex) was in a certain circumstance constituted by the collection {John, Paul, George, Pete} and in another one constituted by the collection {John, Paul, George, Ringo}. The replacement of Pete Best by Ringo Star does not alter the identity of the band, but creates a different group of people.

FunctionalComplex
type: Class
subclass of: Object
comment: isComponentOf
comment: A complex gufo:Object whose parts (components) play different roles in its composition. For example, a person could be considered a gufo:FunctionalComplex with the various organs (heart, brain, lungs, etc.) playing different roles. Another example is a scrum team, which is composed by people playing the roles of scrum master, product owner, developer, etc. To explicitly capture temporary components, use gufo:TemporaryParthoodSituation.

Individual
type: Class
disjoint with: Type
disjoint union of: AbstractIndividual
disjoint union of: ConcreteIndividual
comment: An entity that (unlike a gufo:Type) cannot be instantiated. Individuals may be either concrete (e.g., the Earth, Mick Jagger, Brazil, the 1985 Mexico City Earthquake) or abstract (e.g., the number two, the proposition that 'three is a prime number'). Also known as "particular" in the philosophical literature.

IntrinsicAspect
type: Class
subclass of: Aspect
subclass of: Restriction
  on property: inheresIn
  qualified cardinality: 1
  on class: ConcreteIndividual
disjoint union of: IntrinsicMode
disjoint union of: Quality
comment: A gufo:Aspect that depends on a single concrete individual in which it inheres. Examples include intrinsic physical aspects, such as the Moon's mass, Lassie's fur color; the fragility of John Lennon's glasses; mental dispositions, such as Bob's math skills, his belief that the number one is odd. A gufo:IntrinsicAspect is classified as a gufo:Quality (e.g., an apple's weight, the height of the Statue of Liberty) if it is measurable by a certain value space, or as a gufo:IntrinsicMode (e.g. Bob's belief that the Eiffel Tower is in Paris) otherwise. Corresponds to "Intrinsic Moment" in Guizzardi (2005). Different from Guizzardi (2005), here we consider that aspects can inhere in concrete individuals in general, and not only in endurants.

IntrinsicMode
type: Class
subclass of: IntrinsicAspect
disjoint with: Quality
comment: A gufo:IntrinsicAspect that is not measurable. For example, Bob's belief that the Eiffel Tower is in Paris, his math skills, his headache. Corresponds to "Mode" in Guizzardi (2005).

Kind
type: Class
subclass of: RigidType
subclass of: Sortal
disjoint with: SubKind
comment: A gufo:EndurantType that is both sortal and rigid. It provides a uniform principle of identity for its instances. Every gufo:Endurant instantiates one and only one gufo:Kind. Examples include kinds of ordinary objects of everyday experience, such as: "Person", "House", "Car"; kinds of relators, such as "Marriage", "RentalContract"; kinds of existentially-dependent aspects of objects, such as "Weight", "Belief", "Vulnerability".

MaterialRelationshipType
type: Class
subclass of: RelationshipType
comment: A gufo:RelationshipType derived from extrinsic aspects of the related entities. For example, "marriedWith", "employedBy", "enrolledIn", "admires". For a gufo:MaterialRelationshipType it is recommended to identify the type of extrinsic aspect from which the material relationship type is derived (see gufo:isDerivedFrom). For example "marriedWith" can be derived from the "Marriage" relator type, "employedBy" can be derived from the "Employment" relator type. Encompasses "Material Relation" in Guizzardi (2005) and corresponds to "Material Relation" in Fonseca et al. (2019).

Mixin
type: Class
subclass of: NonSortal
subclass of: SemiRigidType
comment: A gufo:EndurantType that is both non-sortal and semi-rigid. As a semi-rigid type, it applies necessarily to some of its instances and contingently to some others. As a non-sortal, it captures properties shared by instances of different kinds. For example, the type "FemaleAnimal" may be considered a gufo:Mixin as it applies necessarily to animals of certain species, e.g., lions and sharks, while it applies contingently to animals of other species such as clownfish and mushroom corals (which may change sex given certain conditions).

NonRigidType
type: Class
subclass of: EndurantType
disjoint with: RigidType
disjoint union of: AntiRigidType
disjoint union of: SemiRigidType
comment: A gufo:EndurantType that does not apply necessarily to at least one of its instances (see Guizzardi, 2005, chapter 4). Examples include anti-rigid types, such as the role "Student" and the phase "Child", and semi-rigid types, such as the mixin "MusicalArtist" (which necessarily characterizes bands, but contingently characterizes people) and the mixin "FemaleAnimal" (which is necessarily characterizes female dogs, but contigently characterizes clownfish).

NonSortal
type: Class
subclass of: EndurantType
disjoint with: Sortal
comment: A gufo:EndurantType that applies to individuals of different kinds (see Guizzardi, 2005, chapter 4). Non-sortals do not provide a uniform principle of identity for their instances; instead, they just classify things that share common properties but which obey different principles of identity. Also termed "dispersive" types in the philosophical literature.

Object
type: Class
subclass of: Endurant
comment: A gufo:Endurant that does not depend on another endurant for its existence (excluding its essential parts and aspects). Examples of objects include ordinary physical entities, such as a dog, a house, a tomato, a car, Alan Turing, but also socially-defined entities such as The Rolling Stones, the European Union, the Brazilian 1988 Constitution. Guizzardi (2005) also included the more abstract notion of "Substantial", which generalizes both objects and amounts of matter. That notion was left out from this implementation, together with the notion of amount of matter. Support for the representation of maximally-self-connected amounts of matter is given by gufo:Quantity.

Participation
type: Class
subclass of: Event
subclass of: Restriction
  on property:
    inverse of: participatedIn
  qualified cardinality: 1
  on class: Object
comment: A gufo:Event that depends on a single object. Participations can be used to partition an event into portions, each of which depend exclusively on a single object. Consider a business meeting with multiple participants, including John and Mary. John's participation in the meeting encompasses all events that are part of the meeting and that depend solely on him. Likewise, Mary's participation encompasses all events that are part of the meeting and that depend solely on her. Similarly, in Brutus’ stabbing of Caesar, we may identify the participations of Brutus, of Caesar, and of the dagger.

Phase
type: Class
subclass of: AntiRigidType
subclass of: Sortal
disjoint with: Role
comment: A gufo:EndurantType that is both sortal and anti-rigid. It is defined by intrinsic but contingent instantiation conditions. Phases are relationally independent types that capturec intrinsic properties shared by instances of a given kind. For example, "Child" may be considered a gufo:Phase as a subclass of the gufo:Kind "Person", instantiated by persons younger than 12. Another example is the type "IllPerson", which may be considered a gufo:Phase that is instantiated whenever an instance of "Disease" (a gufo:IntrinsicMode) inheres in a person.

PhaseMixin
type: Class
subclass of: AntiRigidType
subclass of: NonSortal
disjoint with: RoleMixin
comment: A gufo:EndurantType that is both non-sortal and anti-rigid. It is defined by intrinsic but contingent instantiation conditions. Phase mixins are relationally independent types that capture intrinsic properties shared by instances of different kinds. For example, "LivingAnimal" may be considered a gufo:PhaseMixin as a superclass of the phases "LivingPerson" (specializing the gufo:Kind "Person") and "LivingDog" (specializing the gufo:Kind "Dog").

Quality
type: Class
subclass of: IntrinsicAspect
comment: A gufo:IntrinsicAspect that is measurable by some value spaces. A quality may be used to compare individuals, on the basis of the value it takes in a certain quality space (for instance, a position within the RGB spectrum). Examples include the weight of a person, the name of organization, the color of a car, and the duration of a concert.

QualityValue
type: Class
subclass of: AbstractIndividual
comment: A gufo:AbstractIndividual that can be associated with a gufo:Quality reflecting the perception or conception of the quality in a certain value space. Instances of gufo:QualityValue include the rational number 2.5 when used to conceive of the acidity of a portion of wine (in a pH scale), the tuple <38.8897,-77.0089> when used to conceive of the location of a building (in a space formed by latitude and longitude), or the triplet <0,0,0> when used to conceive of the color of a physical object (in a trimensional space formed by red, green and blue color components). Corresponds to "Quale" in Guizzardi (2005). Use this class only for quality values (qualia) that are to be reified in the A-box and associated with a gufo:ConcreteIndividual through the object property gufo:hasReifiedQualityValue. Otherwise, use the gufo:hasQualityValue data property and a literal to determine the quality value.

QualityValueAttributionSituation
type: Class
subclass of: Situation
subclass of: Class
  union of: Restriction
    on property: concernsReifiedQualityValue
    qualified cardinality: 1
    on class: QualityValue
  union of: Restriction
    on property: concernsQualityValue
    cardinality: 1
subclass of: Restriction
  on property: concernsQualityType
  qualified cardinality: 1
  on class: EndurantType
subclass of: Restriction
  on property:
    inverse of: standsInQualifiedAttribution
  qualified cardinality: 1
  on class: Endurant
disjoint with: TemporaryConstitutionSituation
disjoint with: TemporaryInstantiationSituation
disjoint with: TemporaryParthoodSituation
disjoint with: TemporaryRelationshipSituation
comment: A gufo:Situation in which a quality value is temporarily attributed to a gufo:Endurant. A gufo:QualityValueAttributionSituation should be used only for mutable qualities, i.e. those whose value can vary in time. Examples include: the situation in which the value of a bitcoin in Euros is 6.526,12, which lasted from 10/12/2019 to 11/12/2019; the situation in which the weight of Mike Tyson was 100 kg; and the situation in which the color of Einstein' hair was grey. This is a reification of the quality value attribution (in a solution that is similar to the qualified relation pattern http://patterns.dataincubator.org/book/qualified-relation.html )

Quantity
type: Class
subclass of: Object
comment: A complex gufo:Object that is a maximally-connected portion of stuff. A gufo:Quantity has a fixed constitution, and thus, removing or adding a sub-quantity would result in a different quantity. Examples include the portion of wine in a wine tank, a lump of clay, the gold that constitutes a wedding ring. Also termed "quantity of matter", "objectified portion of matter", "piece" in the philosophical literature.

RelationshipType
type: Class
subclass of: Type
comment: A gufo:Type whose instances are ordered pairs of related entities. Instances of gufo:RelationshipType are object properties in UFO-based ontologies. The object properties "marriedWith" and "enrolledIn" are examples of material relationship types. The object properties "heavierThan", "olderThan" are examples of comparative relationship types. The use of gufo:RelationshipType and its subclasses requires OWL 2 punning. Corresponds to "Relation" in Guizzardi (2005) and Fonseca et al. (2019).

Relator
type: Class
subclass of: ExtrinsicAspect
subclass of: Restriction
  on property: mediates
  min qualified cardinality: 2
  on class: Endurant
comment: A gufo:ExtrinsicAspect that connects (involves, mediates) two or more concrete individuals. Relators are reified relationships composed of reciprocal extrinsic modes. Examples of relators include John and Mary's marriage (composed of John's obligations towards Mary in the scope of the marriage, Mary's reciprocal claims, Mary's obligations towards John, John's reciprocal claims), Mary's employment contract at Nasa, a covalent bond between two atoms.

RigidType
type: Class
subclass of: EndurantType
comment: A gufo:EndurantType which applies necessarily to its instances (see Guizzardi, 2005, chapter 4). Examples include the types "Agent", "Person", "Animal", "PhysicalObject", "Car", and "Tree".

Role
type: Class
subclass of: AntiRigidType
subclass of: Sortal
comment: A gufo:EndurantType that both sortal and anti-rigid. It is defined by relational instantiation conditions. Roles are relationally dependent types, capturing relational properties shared by instances of a given kind. For example, "Student" may be considered a gufo:Role as a subclass of the gufo:Kind "Person", instantiated by all persons enrolled in a school.

RoleMixin
type: Class
subclass of: AntiRigidType
subclass of: NonSortal
comment: A gufo:EndurantType that is both non-sortal and anti-rigid. It is defined by relational instantiation conditions. Role mixins are relationally dependent types, capturing relational properties shared by instances of different kinds. For example, "Customer" may be considered a gufo:RoleMixin as a superclass of the roles "CorporateCustomer" (specializing the gufo:Kind "BusinessOrganization") and "PersonalCustomer" (specializing the gufo:Kind "Person").

SemiRigidType
type: Class
subclass of: NonRigidType
comment: A gufo:NonRigidType that applies necessarily to some of its instances and contingently to some others (see Guizzardi, 2005, chapter 4).

Situation
type: Class
subclass of: ConcreteIndividual
comment: A gufo:ConcreteIndividual that is a particular configuration of a part of reality which can be understood as a whole and in which entities stand in relations. A situation may be counterfactual or actual. An actual situation (or in other words, a "fact") "obtains" in a certain time instant or during a time interval. Note that, in Guizzardi et al. (2013), situations were considered to obtain at a specific point in time. Here, instead, they obtain in a time interval when begin and end points differ. The various subclasses of Situation in this implementation are used to capture "mutable" facts which obtain during some time and fail to obtain at other times. This includes the contingent instantiation of non-rigid types (e.g., as someone is a child at one point in time and a teenager later), the attribution of value to mutable qualities (such as a person's weight) and temporary participation in part-whole relations for replaceable parts (such as a car's tires). Other subclasses may be created to capture domain-specific notions such as "HazardousSituation", "PersonHasFever".

SituationType
type: Class
subclass of: ConcreteIndividualType
comment: A gufo:Type whose instances are situations. Instances of gufo:SituationType are subclasses of gufo:Situation. Examples include "HazardousSituation", "PersonHasFever", "PersonIsStudent".

Sortal
type: Class
subclass of: EndurantType
comment: A gufo:EndurantType which carries (or supplies) a principle of identity for its instances (see Guizzardi, 2005, chapter 4).

SubKind
type: Class
subclass of: RigidType
subclass of: Sortal
comment: A gufo:EndurantType that is both sortal and rigid. It specializes a gufo:Kind carrying the principle of identity supplied by that kind. Every gufo:SubKind should directly or indirectly specialize a gufo:Kind. For example, the gufo:Kind "Lion" may be specialized into the "Lionness" and "Male Lion" subkinds, while the gufo:Kind "Computer" may be specialized into the "Laptop" and "Desktop" subkinds.

TemporaryConstitutionSituation
type: Class
subclass of: Situation
subclass of: Restriction
  on property: concernsConstitutedEndurant
  qualified cardinality: 1
  on class: Object
subclass of: Restriction
  on property:
    inverse of: standsInQualifiedConstitution
  qualified cardinality: 1
  on class: Object
disjoint with: TemporaryInstantiationSituation
disjoint with: TemporaryRelationshipSituation
comment: A gufo:Situation in which a gufo:Endurant temporarly constitutes another gufo:Endurant. When constitution of an object may change in time, it may be qualified by the period in time in which the relation applies. Examples include: the situation in which the Beatles is constituted by the group composed of {John,Paul,Ringo,George}; and the situation in which the statue of Venus de Milo was constituted by its original quantity of marble (including its arms). This is a reification of constitution (in a solution that is similar to the qualified relation pattern http://patterns.dataincubator.org/book/qualified-relation.html)

TemporaryInstantiationSituation
type: Class
subclass of: Situation
subclass of: Restriction
  on property: concernsNonRigidType
  qualified cardinality: 1
  on class: NonRigidType
subclass of: Restriction
  on property:
    inverse of: standsInQualifiedInstantiation
  qualified cardinality: 1
  on class: Endurant
disjoint with: TemporaryParthoodSituation
disjoint with: TemporaryRelationshipSituation
comment: A gufo:Situation in which a gufo:Endurant temporarily instantiates a gufo:NonRigidType. A gufo:TemporaryInstantiationSituation can account for the time period in which a particular instantiation holds. Examples include: the situation in which Obama instantiates the role of president, which began in 20/01/2009 and lasted until 20/01/2017; the situation in which Coatria instantiates the role of EU Member, which began in 01/07/2013 (and is still on-going); and the situation in which Steve Jobs instantiates the child phase, which began in 24/02/1955 and lasted until 24/02/1965. This solution is inspired in the qualified relation pattern (http://patterns.dataincubator.org/book/qualified-relation.html).

TemporaryParthoodSituation
type: Class
subclass of: Situation
subclass of: Restriction
  on property: concernsTemporaryWhole
  qualified cardinality: 1
  on class: Endurant
subclass of: Restriction
  on property:
    inverse of: standsInQualifiedParthood
  qualified cardinality: 1
  on class: Endurant
disjoint with: TemporaryRelationshipSituation
comment: A gufo:Situation in which a gufo:Endurant is temporarily a part of another gufo:Endurant. A gufo:TemporaryParthoodSituation should only be used for mutable parts. It may be qualified by the period in time in which the relation applies. Examples include: the situation in which the United Kingdom is a member of the European Union; the situation in which Messi is a a member of the Barcelona FC squad; the situation in which an engine is part of a car; and the situation in which a transplanted heart is part of a person. Note that, since every instance of gufo:Quantity or gufo:FixedCollection only has essential parts, the gufo:TemporaryParthoodSituation should not be used to represent these parthood relations. This solution is inspired in the qualified relation pattern (http://patterns.dataincubator.org/book/qualified-relation.html).

TemporaryRelationshipSituation
type: Class
subclass of: Situation
subclass of: Restriction
  on property: concernsRelatedEndurant
  some values from: Endurant
subclass of: Restriction
  on property: concernsRelationshipType
  qualified cardinality: 1
  on class: RelationshipType
subclass of: Restriction
  on property:
    inverse of: standsInQualifiedRelationship
  qualified cardinality: 1
  on class: Endurant
comment: A gufo:Situation in which a gufo:Endurant temporarily stands in a relation with another gufo:Endurant (or other endurants in the case of n-ary relationships). Reification of a gufo:TemporaryRelationshipSituation allows qualification of the relationship with the period in time in which it applies. Examples include: the situation in which Einstein works at the Swiss Patent Office in Bern; the situation in which Elon Musk studies at the University of Pennsylvania; the situation in which John Lennon is married to Yoko Ono; and the situation in which Facebook has a lower market value than Amazon. For material relationships, prefer the use of gufo:Relator. This is a reification of the relationship (in a solution that is similar to the qualified relation pattern http://patterns.dataincubator.org/book/qualified-relation.html).

Type
type: Class
comment: An entity that may be instantiated by (or predicated over) other entities. Types encompass what we often call "sorts", "kinds", "categories", etc. Examples include the kind "Person", the event type "Earthquake", and the abstract individual type "NaturalNumber". Relations, such as "marriedTo" and "olderThan", are also considered as types. Instances of gufo:Type are classes, and should specialize the taxonomy of individuals of gUFO. For example, "Person" is a gufo:Type (more specifically a gufo:Kind), specializing gufo:Object. The mechanism that allows for this is called punning in OWL 2. Encompasses the notion of "Universal" in Guizzardi (2005).

VariableCollection
type: Class
subclass of: Collection
comment: TemporaryParthoodSituation
comment: A gufo:Collection for which change in membership is possible. Such a collection obeys an intensional principle of identity, i.e., change in membership does not necessarily create a different collection. For example, KLM's fleet of airplanes could be understood as a gufo:VariableCollection. In this case, when the company acquires (or retires) an airplane, the fleet changes. Note that, in this case, the airplanes are conceptualized as playing the role of "member of a fleet". If various roles for the parts of a fleet were envisioned (such as "cargo airplane", "passenger airplane"), then a fleet would be best understood as a gufo:FunctionalComplex. See gufo:TemporaryParthoodSituation for the pattern to represent the relation of a variable collection to its temporary parts.

Instant
type: Class
subclass of: AbstractIndividual
comment: An gufo:AbstractIndividual that reifies time instants. It is used as a target of the gufo:hasBeginPoint and gufo:hasEndPoint object properties.

Acquaintance Relationship
type: Class
subclass of: Interpersonal Relationship
definition: An interpersonal relationship of social acquaintance — agents who have met and know one another (the reified form of hasMet).

Activity
type: Class
subclass of: Event
definition: Something that occurs over a period of time and acts upon or with entities — creating, transforming, using, or attributing them.

Address Tenure
type: Class
subclass of: Time-Scoped Relation
definition: The reified, time-scoped fact that an agent held a contact point (e.g. an email address) over a particular interval.

Adoption
type: Class
subclass of: Life Event
definition: The adoption of a person.

Adoptive Parent-Child
type: Class
subclass of: Parent-Child Relationship
definition: A parent-child relationship established by adoption.

Agent
type: Class
subclass of: FunctionalComplex
subclass of: Entity
definition: An entity that can act, bear responsibility, and enter into agreements: a person, an organization, or a software agent.

Agreement
type: Class
subclass of: Relator
definition: A mutual understanding between two or more agents that creates obligations or rights, reified as a relator connecting its parties.

Annulment
type: Class
subclass of: Life Event
definition: The annulment of a marriage.

Article
type: Class
subclass of: Creative Work
definition: A written work published in a periodical, blog, or scholarly venue.

Attachment
type: Class
subclass of: Body Part
definition: A non-inline body part presented as an attached file. An attachment may also be a gmeow:Document or gmeow:MediaObject (the two are not disjoint), and its text extraction or summary is a derived object linked by gmeow:wasDerivedFrom.

Authentication Result
type: Class
subclass of: Information Object
definition: The outcome of an email authentication check (RFC 8601 Authentication-Results) — a method (DKIM, SPF, DMARC, ARC), a verdict, and the verifying server.

Baptism
type: Class
subclass of: Life Event
definition: A baptism.

Bar Mitzvah
type: Class
subclass of: Life Event
definition: A bar mitzvah.

Bat Mitzvah
type: Class
subclass of: Life Event
definition: A bat mitzvah.

Biological Parent-Child
type: Class
subclass of: Parent-Child Relationship
definition: A parent-child relationship by biological descent.

Birth
type: Class
subclass of: Life Event
definition: The event of a person being born.

Body Part
type: Class
subclass of: Information Object
definition: A MIME part of a message's body, with a media type and content.

Burial
type: Class
subclass of: Life Event
definition: The burial of a deceased person.

Census
type: Class
subclass of: Life Event
definition: A person's enumeration in a census.

Certification
type: Class
subclass of: Relator
definition: A reified attestation that a cryptographic key belongs to a given identity, made by a certifying agent (a PGP key-signature / Web-of-Trust certification). Its validity window is carried with gmeow:validFrom/validUntil; revocation sets validUntil.

Christening
type: Class
subclass of: Life Event
definition: A christening or naming ceremony.

Citation
type: Class
subclass of: Information Object
definition: A reference to a specific place within a source (a page, entry, image, or record locator).

Confirmation
type: Class
subclass of: Life Event
definition: A religious confirmation.

Contact Point
type: Class
subclass of: Object
subclass of: Entity
definition: A means of reaching an agent: an email address, telephone number, or postal address.

Contract
type: Class
subclass of: Agreement
definition: A legally enforceable agreement.

Couple Relationship
type: Class
subclass of: Kin Relationship
definition: A reified couple relationship (marriage, civil union, or partnership) between two persons; bears marriage, divorce and related events.

Creative Work
type: Class
subclass of: Information Object
definition: An information artifact resulting from creative or intellectual effort — a document, article, dataset, media object, or web page.

Credential
type: Class
subclass of: Entity
definition: An educational or occupational credential held by an agent — a degree, certification, or license.

Cremation
type: Class
subclass of: Life Event
definition: The cremation of a deceased person.

Cryptographic Key
type: Class
subclass of: Information Object
definition: A public key, certificate, or key material bound to an agent's identity — the thing a signature is made with and a certification vouches for.

Cryptographic Signature
type: Class
subclass of: Information Object
definition: A cryptographic signature over a message or its headers, asserting origin and integrity.

DKIM Signature
type: Class
subclass of: Cryptographic Signature
definition: A DomainKeys Identified Mail signature (RFC 6376) over selected headers and the body.

Dataset
type: Class
subclass of: Creative Work
definition: A collection of data published as a unit.

Death
type: Class
subclass of: Life Event
definition: The event of a person's death.

Divorce
type: Class
subclass of: Life Event
definition: The legal dissolution of a marriage.

Document
type: Class
subclass of: Creative Work
definition: A bounded textual or digital document — a file, record, or report.

Email Address
type: Class
subclass of: Contact Point
definition: A contact point reachable via the Simple Mail Transfer Protocol (SMTP).

Email Message
type: Class
subclass of: Message
definition: An RFC 5322 email message, with headers, participants, a thread, body parts and mailbox residence.

Emigration
type: Class
subclass of: Life Event
definition: A person's emigration from a country.

Engagement
type: Class
subclass of: Life Event
definition: A betrothal or engagement to marry.

Entity
type: Class
subclass of: Endurant
definition: Anything in the GMEOW universe of discourse that persists in time and can bear properties: an agent, a document, a contact point, and so on.

Family
type: Class
subclass of: Group
definition: A kinship group of persons related by descent, marriage, or adoption.

First Communion
type: Class
subclass of: Life Event
definition: A first communion.

Foster Parent-Child
type: Class
subclass of: Parent-Child Relationship
definition: A parent-child relationship through fostering.

Funeral
type: Class
subclass of: Life Event
definition: A funeral or memorial service.

Geo Coordinates
type: Class
subclass of: Entity
definition: A geographic point expressed as latitude and longitude.

Graduation
type: Class
subclass of: Life Event
definition: Graduation from an educational program.

Group
type: Class
subclass of: Collection
subclass of: Entity
definition: A collection of agents treated as a unit without the formal structure of an organization.

Immigration
type: Class
subclass of: Life Event
definition: A person's immigration into a country.

Information Object
type: Class
subclass of: Object
subclass of: Entity
definition: An entity whose nature is to carry information content: a document, dataset, software artifact, online account, or message. The shared parent of the document, software and account layers.

Interpersonal Relationship
type: Class
subclass of: Relator
definition: A reified standing relationship between agents (acquaintance, collaboration, …), able to bear its own time interval, confidence, and source evidence.

Key Scheme
type: Class
subclass of: Entity
definition: The cryptographic scheme/format of a key (OpenPGP, X.509, SSH, Nostr, …). Modelled as a value, not a key subclass: the set of schemes is open-ended and they carry no distinct key structure here, so a new scheme is a new individual, not a new class.

Kin Relationship
type: Class
subclass of: Relator
definition: A reified kinship relationship between persons, able to bear its own events, dates and sources.

Life Event
type: Class
subclass of: Activity
definition: An event in the life of a person or family — with a date, a place, and participating persons — to which sources and confidence can be attached.

Mailbox
type: Class
subclass of: Information Object
definition: A named container of messages within an account — a folder, JMAP mailbox, or Gmail label.

Mailbox Residence
type: Class
subclass of: Time-Scoped Relation
definition: The reified, time-scoped fact that a message resided in a mailbox/label over an interval (membership is time-varying — messages move between folders and labels).

Marriage
type: Class
subclass of: Life Event
definition: The event of two persons entering into marriage.

Media Object
type: Class
subclass of: Creative Work
definition: An image, audio, or video media file.

Membership
type: Class
subclass of: Relator
definition: The reified relationship by which an agent is a member of an organization, optionally playing a role over a period of time.

Message
type: Class
subclass of: Information Object
definition: A communication sent from one agent to others — the parent of email and other message kinds.

Message Header
type: Class
subclass of: Information Object
definition: A single RFC 5322 header field (name and value) of a message.

Message Keyword
type: Class
subclass of: Entity
definition: A flag/keyword applied to a message (IMAP flag or JMAP keyword) such as seen, flagged, answered, draft, forwarded, or junk.

Military Service
type: Class
subclass of: Life Event
definition: A period of military service.

Name Change
type: Class
subclass of: Life Event
definition: A formal change of name.

Naturalization
type: Class
subclass of: Life Event
definition: The grant of citizenship by naturalization.

Occupation
type: Class
subclass of: Entity
definition: A kind of work or profession, such as those classified by ESCO or SOC.

Online Account
type: Class
subclass of: Information Object
definition: An account an agent holds with an online service — a social profile, code-forge account, or decentralized identity.

Ordination
type: Class
subclass of: Life Event
definition: Ordination into religious office.

Organization
type: Class
subclass of: Agent
definition: A structured group of agents — a company, institution, association, or governmental body — able to act as a single agent.

PGP Signature
type: Class
subclass of: Cryptographic Signature
definition: An OpenPGP signature (RFC 4880/9580, PGP-MIME RFC 3156) over a message, bound to a PGP key.

Parent-Child Relationship
type: Class
subclass of: Kin Relationship
definition: A reified parent-child relationship, typed by its nature (biological, adoptive, step, or foster).

Patent
type: Class
subclass of: Creative Work
definition: A granted or filed patent describing an invention.

Person
type: Class
subclass of: Agent
definition: An individual human being, living or deceased.

Person Name
type: Class
subclass of: Information Object
definition: A structured, typed name borne by a person — birth name, married name, alias — with ordered name parts and an optional validity period.

Place
type: Class
subclass of: Object
subclass of: Entity
definition: A geographic location: a country, city, building, or point of interest.

Postal Address
type: Class
subclass of: Contact Point
definition: A contact point reachable by physical mail at a postal address.

Probate
type: Class
subclass of: Life Event
definition: The probate of an estate.

Professional Relationship
type: Class
subclass of: Interpersonal Relationship
definition: An interpersonal relationship arising from work — colleagues, collaborators, a client and a provider (the reified form of hasWorkedWith).

Relay Hop
type: Class
subclass of: Event
definition: One hop in a message's delivery path, recorded by a Received header: a relaying server, the host it received from, a server timestamp, and the protocol used.

Repository
type: Class
subclass of: Information Object
definition: A version-control repository holding the source code of a software project.

Residence
type: Class
subclass of: Life Event
definition: A person's residence at a place over a period.

Retirement
type: Class
subclass of: Life Event
definition: Retirement from working life.

Role
type: Class
subclass of: Role
definition: A function or position an agent plays in some context, such as a job title or organizational role.

S/MIME Signature
type: Class
subclass of: Cryptographic Signature
definition: An S/MIME signature (RFC 8551) over a message, bound to an X.509 certificate.

Separation
type: Class
subclass of: Life Event
definition: A legal or informal marital separation.

Skill
type: Class
subclass of: Entity
definition: A competency or ability an agent possesses.

Software Agent
type: Class
subclass of: Agent
definition: A software process or autonomous program that acts on behalf of a person or organization.

Software Project
type: Class
subclass of: Creative Work
definition: A software project: a body of source code developed and released as a unit, with repositories, releases, and contributors.

Source
type: Class
subclass of: Information Object
definition: A source from which evidence is drawn: a record, certificate, register, archive entry, or publication.

Step Parent-Child
type: Class
subclass of: Parent-Child Relationship
definition: A parent-child relationship through marriage to a biological/adoptive parent.

Summary
type: Class
subclass of: Information Object
definition: A condensed account derived from a source information object (often machine-generated), linked to its source by gmeow:wasDerivedFrom.

Telephone Number
type: Class
subclass of: Contact Point
definition: A contact point reachable by telephone.

Text Extraction
type: Class
subclass of: Document
definition: The text content extracted from a source object (e.g. a PDF attachment), linked to its source by gmeow:wasDerivedFrom.

Thread
type: Class
subclass of: Information Object
definition: A conversation: a set of messages related by reply/reference chains.

Time Interval
type: Class
definition: A bounded stretch of time, optionally open-ended, delimited by a start and/or end instant.

Time-Scoped Relation
type: Class
subclass of: Situation
definition: A reified relationship that holds only over a particular time interval — the base for residence, tenure, and membership-over-time situations.

Trust Assertion
type: Class
subclass of: Relator
definition: A reified, perspectival assertion that one agent (the trustor) trusts another (the trustee), optionally as an introducer to a given depth — the OpenPGP owner-trust notion. Its validity window is carried with gmeow:validFrom/validUntil.

Web Page
type: Class
subclass of: Creative Work
definition: A page on the web identified by a URL.

Will
type: Class
subclass of: Life Event
definition: The making of a will.

Nostr
type: NamedIndividual
type: Key Scheme

OpenPGP
type: NamedIndividual
type: Key Scheme

SSH
type: NamedIndividual
type: Key Scheme

X.509
type: NamedIndividual
type: Key Scheme

answered
type: NamedIndividual
type: Message Keyword

draft
type: NamedIndividual
type: Message Keyword

flagged
type: NamedIndividual
type: Message Keyword

forwarded
type: NamedIndividual
type: Message Keyword

junk
type: NamedIndividual
type: Message Keyword

seen
type: NamedIndividual
type: Message Keyword