object/rel/possessor

Semantics:
[[m]] is the proposition that [[i]] is a [[k]] of [[j]];
or: [[m]] is the proposition that [[i]] is [[j]]'s [[k]];
or: [[m]] is the proposition that [[i]] is possessed (in some unspecified way) by [[j]] and the relationship of [[i]] to [[j]] is [[k]].

Example:
Fido is John's dog.
(assert object #Fido rel (build lex "dog") possessor #john)
[(assert member *Fido class (build lex "dog"))]
(assert object #john proper-name (build lex "John"))

NOTE: The bracketed assertion above can be eliminated in favor of a node-based rule to the effect that if [[i]] is [[j]]'s [[k]], then [[i]] is a [[k]].