A novel method, the circuit simulation algorithm, is proposed here, which transfers the graph isomorphism problem into the identical circuits problem.

For the subclasses MAX and MARG of minimal unsatisfiable formulas, we show that the variable and literal renaming problems are equivalent to the graph isomorphism problem GI.

Isomorphism identification is an important and difficult problem in mechanism type synthesis, it is also one of the most difficult problems in graph theory.