A Simulation of Co-identity with Rules in Simple and Nested Graphs

Equality of markers ajid co-reference links have always been a convenient way to denote that two concept nodes represent the same entity in conceptual graphs. This is the underlying cause of counterexamples to projection completeness with respect to these graphs FOL semantics. Several algorithms and semantics have been proposed to achieve completeness, but they do not always suit &a application specific needs. In this paper, I propose to represent identity by relation nodes, which are first-class objects of the model, and I show that conceptual graphs rules can be used to represent and simulate reasonings defined by various semantics assigned to identity, be it in the case of simple or nested graphs. The interest of this method is that we can refine these rules to manage the identity needed by the application.