18 and 25 Feb 2004
CS 3243 - Logical Agents
68
Hard satisfiability problems
nConsider random 3-CNF sentences. e.g.,
n (ØD Ú ØB Ú C) Ù (B Ú ØA Ú ØC) Ù (ØC Ú  ØB Ú E) Ù (E Ú ØD Ú B) Ù (B Ú E Ú ØC)
n
nm = number of clauses
nn = number of symbols
n
nHard problems seem to cluster near m/n = 4.3 (critical point)