CS 540Lecture NotesSpring 2001

First-Order Logic (Chapters 7 - 9)

First-Order Logic (FOL or FOPC) Syntax

Translating English to FOL

Inference Rules for FOL

Automated Inference for FOL

Resolution Refutation Procedure (aka Resolution Procedure)


Resolution Refutation Procedure (aka Resolution Procedure)

Example using PL Sentences

Problems Yet to Be Addressed

Converting FOL Sentences to Clause Form

Revised Resolution Refutation Procedure

procedure resolution-refutation(KB, Q)
   ;; KB is a set of consistent, true FOL sentences
   ;; Q is a goal sentence that we want to derive
   ;; return success if KB |- Q, and failure otherwise
   KB = union(KB, ~Q)
   KB = clause-form(KB)  ; convert sentences to clause form
   while false not in KB do
     pick 2 clauses, C1 and C2, that contain literals that unify
     if none, return "failure"
     resolvent = resolution-rule(C1, C2)
     KB = union(KB, resolvent)
   return "success"

Example: Hoofers Club

Resolution Procedure as Search through a Search Space

Last modified October 14, 1998
Copyright © 1996 by Charles R. Dyer. All rights reserved.