Unified Foundational Ontology (UFO)
This is just a quick reference guide and should not be taken as a source of truth about OntoUML specification.
Ontology is a branch of philosophy that studies concepts such as existence, its nature, and its relationships. While we can have examples of ontologies in a specific domain, an ontology can also be a foundational one, defining aspects that are independent of a domain. Giancarlo Guizzardi proposes in his work a foundational ontology called UFO (Unified Foundational Ontology) through the composition of several theories from areas such as linguistics and formalizations of ontologies of philosophy. This ontology is divided into three parts: UFO-A, UFO-B, and UFO-C.
For the scope of this work, we will talk mostly about UFO-A, which is an ontology of endurants, and UFO-B, which is an ontology of perdurants. "Endurants are individuals that exist in time with all their parts. They have essential and accidental properties and, hence, they can qualitatively change while maintaining their numerical identify (i.e., while remaining the same individual)". Billie Eilish, the Moon, and John's weight are all examples of endurants. On the other hand, we have elements that are Perdurants in contrast to Endurants. "Perdurants are individuals that unfold in time accumulating temporal parts. An endurant can change while maintaining its identity, a perdurant cannot". An example of perdurant is the event of composing a new song, made by an artist.
Figure: Diagram describing UFO taxonomy.