One week ago, I asked a question on math.stackexchange.com (http://math.stackexchange.com/questions/209120/a-question-on-intuitionistc-propositional-logic) . But nobody answered my question. So I presented it here:
In the Kripke's semantics of intuitionistic propositional logic, the frames are all partial ordered frames. Prove that:
Two finite rooted frames are isomorphic iff they validate the same formulas in the langusge of intuitionistic propositional logic.
Thanks very much.