# Homomorphism Proof Systems for Unsatisfiable Formulas

@inproceedings{Dao2005HomomorphismPS, title={Homomorphism Proof Systems for Unsatisfiable Formulas}, author={Xu Dao}, year={2005} }

A homomorphism ? of CNF formulas from H to F is a function mapping the set of literals in H to the set of literals in F and it preserves complements and clauses. If the formula H is homomorphic to the formula F, then the unsatisfiability of H implies the unsatisfiability of F. A CNF formula F is minimally unsatisfiable if F is unsatisfiable and the resulting formula deleting any one clause from F is satisfiable. MU(1) is a class of minimally unsatisfiable formulas with the deficiency of the… CONTINUE READING