This ontology contains logical relations to be shared across the different OBO ontologies. Each OBO ontology is free to extend this set with relations specific to the biology within that ontology
In the definitions, variables c, d, ..., p, q, ... range over instances of continuants and processes respectively. C, D, ..., P, Q, ... range over the corresponding classes
For a discussion of instance-level relations and also of additional axioms needed to infer transitivity and other properties of the relations listed above see http://genomebiology.com/2005/6/5/R46 or the OBO relations page hosted at http://obo.sourceforge.net/relationship