Compiling Problem Speci cations into SAT

We present a compiler that translates a problem speciica-tion into a propositional satissability test (SAT). Problems are speciied in a logic-based language, called np-spec, which allows the deenition of complex problems in a highly declarative way, and whose expressive power is such to capture exactly all problems which belong to the complexity class NP. The target SAT instance is solved using any of the various state-of-the-art solvers available from the community. The system obtained is an executable speciication language for all NP problems which shows interesting computational properties. The performances of the system have been tested on a few classical problems, namely graph coloring, Hamiltonian cycle, and job-shop scheduling.