The complexity of homomorphisms and renamings for minimal unsatisfiable formulas
We investigate the complexity of deciding whether for minimal unsatisfiable formulas F and H there exists a variable renaming, a literal renaming or a homomorphism phi such that phi(F) = H. A variable renaming is a permutation of variables. A literal renaming is a permutation of variables which additionally replaces some of the variables by its complements. A homomorphism can be considered as a literal renaming which can map different literals to one literal.
complexity homomorphism renaming minimal unsatisfiable formula graph isomorphism