System Description: SPASS-FD

Using a constrained superposition calculus and a disunification procedure, it is possible to employ superposition-based first-order reasoners for reasoning not only about all models of a first-order theory, but also about all models over a specific finite domain and often as well about the perfect models of the theory (or the unique minimal model in case of a Horn theory), both of which are second-order problems. In this paper, I describe the tool Spass-FD, an extension of the firstorder prover Spass that equips Spass with disunification and with fixed domain and minimal model theorem proving capabilities.