Vol. 15 No. 4, © The Author, 2005. Published by Oxford University Press. All rights reserved.
Original Articles |
Approximating Succinct MaxSat
1 Institut für Informatik (I7) TU München, Boltzmannstraße 3, D-85748 Garching bei München, Germany. Email: schallha{at}in.tum.de, 2 University of California at Berkeley, Computer Science Division, 615 Soda Hall, Berkeley, CA 94720-1776, USA. Email: luca{at}eecs.berkeley.edu
We study the approximability of the version of MAXSAT where exponentially large instances are succinctly represented using circuits. First, we prove that the NP-hardness for approximating MAXSAT can be lifted to a corresponding NEXP-hardness for approximating circuit-succinct MAXSAT for some constant performance ratio. Second, we consider the approximability of circuit-succinct MAXSAT with respect to lower complexity classes: in particular, we prove that computing (2
)-approximate solutions for circuit-succinct MAXSAT is at least as hard as inverting one-way permutations. On the other hand, a simple randomized approximation algorithm computes a (2 +
)-approximate solution with high probability. Recall that the standard (not succinctly represented) version of the MAXSAT problem is approximable to within a 0.78 factor and that the MAX3SAT problem is approximable to within a 7/8 factor.
Keywords: Approximation, succinctness, SAT
Received 29 May 2005.