Redundancy in logic II: 2CNF and Horn propositional formulae

Paolo Liberatore
2008 Artificial Intelligence  
We report results about the redundancy of formulae in 2CNF form. In particular, we give a slight improvement over the trivial redundancy algorithm and give some complexity results about some problems related to finding Irredundant Equivalent Subsets (I.E.S.) of 2CNF formulae. The problems of checking whether a 2CNF formula has a unique I.E.S. and checking whether a clause in is all its I.E.S.'s are polynomial. Checking whether a 2CNF formula has an I.E.S. of a given size and checking whether a
more » ... lause is in some I.E.S.'s of a 2CNF formula are polynomial or NP-complete depending on whether the formula is cyclic. Some results about Horn formulae are also reported.
doi:10.1016/j.artint.2007.06.003 fatcat:rxgiyj65gvbnpautp6zax6w2ve