theorem prover from Microsoft Research

 Z3 is a state-of-the art theorem prover from Microsoft Research. It can be
 used to check the satisfiability of logical formulas over one or more
 theories. Z3 offers a compelling match for software analysis and verification
 tools, since several common software constructs map directly into supported
 theories.
 .
 The Z3 input format is an extension of the one defined by the SMT-LIB 2.0
 standard.