25 February 2004
CS 3243 - Logical Agents (part 2)
10
Resolution
nConjunctive Normal Form (CNF)
n   conjunction of disjunctions of literals
n clauses
n E.g., (A Ú ØB) Ù (B Ú ØC Ú ØD)
n
nResolution inference rule (for CNF):
nli Ú… Ú lk,  m1 Ú … Ú mn
nli Ú … Ú li-1 Ú li+1 Ú … Ú lk Ú m1 Ú … Ú mj-1 Ú mj+1 Ú... Ú mn 
n
n where li and mj are complementary literals.
n E.g., P1,3 Ú P2,2, ØP2,2
n     P1,3
n
nResolution is sound and complete
for propositional logic