Resolution and other satisfiability methods in SSReflect Ports to SSReflect of: Constable, Moczydlowski, [2007] "Extracting the Resolution Algorithm from a Completeness Proof for the Propositional Calculus" https://github.com/acorrenson/SATurne https://www.isa-afp.org/theories/propositional_proof_systems/#Sema_Craig.html