Extracting the Resolution Algorithm from a Completeness Proof for the Propositional Calculus

  • Authors:
  • Robert Constable;Wojciech Moczydłowski

  • Affiliations:
  • Department of Computer Science, Cornell University, Ithaca, NY 14853, USA;Department of Computer Science, Cornell University, Ithaca, NY 14853, USA

  • Venue:
  • LFCS '07 Proceedings of the international symposium on Logical Foundations of Computer Science
  • Year:
  • 2007

Quantified Score

Hi-index 0.00

Visualization

Abstract

We prove constructively that for any propositional formula 驴in Conjunctive Normal Form, we can either find a satisfying assignment of true and false to its variables, or a refutation of 驴showing that it is unsatisfiable. This refutation is a resolution proof of ¬驴. From the formalization of our proof in Coq, we extract Robinson's famous resolution algorithm as a Haskell program correct by construction. The account is an example of the genre of highly readable formalized mathematics.