Ontology

In Ontohub, an ontology consists of a set of symbols and a set of sentences:

• A symbol is an atomic expression or syntactic constituent that may be used in axioms. (Moreover, an semantic interpretation or model of an ontology usually consists of an interpretation of all the symbols.)
  • Symbols have different kinds, for example, in OWL, there a classes, object properties, individuals etc. (In other logics,

there are other kinds of symbols.) For each symbol, there is a tab displaying the symbols of that kind. kind, there is a

• A sentence (formula) is a logical expression constraining the meaning (interpretation) of the ontology and often thereby linking different symbols.
  • A sentence may be an axiom (i.e. it is postulated to be true) a conjecture (i.e. it is postulated to follow from the axioms),

or a theorem (i.e. it has been proven to follow from the axioms).

Ontologies are defined in files. An ontology may be defined as single ontology in one file, or it may be part of an ontology library, which in turned is defined in a file.

Ontologies can be annotated with comments and metadata.