On Semidefinite Programming Relaxations of (2

Recently, De Klerk, Van Maaren and Warners [7] investigated a relaxation of 3-SAT viasemidefinite programming. Thus a 3-SAT formula is relaxed to a semidefinite feasibilityproblem. If the feasibility problem is infeasible then a certificate of unsatisfiability ofthe formula is obtained. The authors proved that this approach is exact for severalpolynomially solvable classes of logical formulae, including 2-SAT, pigeonhole formulaeand mutilated chessboard formulae.In this paper we further...