Computer Science and Information Engineering, World Congress on (2009)
Los Angeles, California USA
Mar. 31, 2009 to Apr. 2, 2009
DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/CSIE.2009.690
A clause set is renamable Horn if the result replacing part propositional variable with its complement is a set of Horn clauses. The renamable Horn problem is solvable in linear time, but the maximum renamable Horn problem (MAX-RHS) is NP-hard. In this paper, we present transformations between clause sets and undirected graphs in polynomial time, such that finding a renamable Horn subset of a clause set is equivalent to finding an independent set of vertices of a graph. Then, the problems MAX-RHS and MAX-IND have the same complexity, and MAX-RHS is inapproximable.
maximum renamable Horn set, maximum independent set, polynomial transformation, NP-Hardness, inapproximability
Y. Qin and D. Xu, "Maximum Renamable Horn and Maximum Independent Sets," 2009 WRI World Congress on Computer Science and Information Engineering, CSIE(CSIE), Los Angeles, CA, 2009, pp. 743-747.