Edu:Relation
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Relation
Disambiguation: the term as used in the literature can refer to either one of the following, depending on the context:
- Instance-level entity
- Type-level entity, used interchangeably with, mainly, relationship (e.g., in Entity-Relationship diagrams), association (UML class diagrams), and object property (in OWL)
- Its definitions in mathematics, notably logic
Definitions
D1 (as instance-level entity)
- A relation is an entity that asserts a (meaningful) connection between two or more other entities, where the entities are individuals, such as objects, processes, or qualities.
D2 (as type-level entity)
- A relation is an entity that asserts a (meaningful) connection between two or more other entities, where the entities are generally denoted with class/ concept/ universal.
Definition Variants
V1 [ MacBride, 2016 ]
- Relations hold between things, or, alternatively, relations are borne by one thing to other things, or, another alternative paraphrase, relations have a subject of inherence whose relations they are and termini to which they relate the subject.
V2 [ Chen, 1976 ]
- A relationship set, R, is a mathematical relation among n entities, each taken from an entity set: {(e1, e2, ..., en) | e1 ∈ E1, e2 ∈ E2, ..., en ∈ En}, and each tuple of entities, (e1, e2, ..., en), is a relationship.
V3 [ Arp et al., 2015 ]
- The manner in which two or more entities are associated or connected together. BFO recognizes three basic types of relation: connecting universal to universal, universal to particular, and particular to particular.
- Domain and range/codomain, also called, more generally, relata
- Relational properties / property characteristics
- The entities mentioned in the definitions above may be one and the same; if that is the case, then that relation is called a recursive relation.
