Equivalence between Two Objects

• The necessary and sufficient conditions for two objects Di and Qi to match:

  • Di and Qi has the same context-free semantics;
  • The relations between Di and its context objects must match those between Qi and its context objects;
  • The context objects of Di and Qi have the same context-free semantics.

• The similarity can be defined by the node-level similarities together with the arc-level similarities.