The Heuristic Theorem Prover: Yet another SMT Modulo Theorem Prover (Tool Paper)

HTP is an SMT Modulo theorem prover similar to many others.[2–6, 9, 11] As input, HTP accepts problems using the SMT-LIB format[8]. As output, HTP will answer either SAT, UNSAT or UNKNOWN. Alternatively, HTP can be run in a preprocessing mode in which the output is the simplified problem in SMTLIB format. An evidence file showing the derivation in a human readable form can be produced. There is a Treeview application which shows this derivation in a tree widget making it convenient to navigate a complex proof. The main contribution of HTP is the introduction of a preprocessor that includes algorithms for detecting unate predicates, eliminating variables, symmetry breaking and boolean encoding. The other algorithms of HTP are similar to other systems. HTP implements a DPLL(T) similar to BarcelogicTools[6]. There are domain theories for equality of uninterpreted function symbols, real difference logic, linear inequality and array logic.