18 and 25 Feb 2004
CS 3243 - Logical Agents
51
Backward chaining
Idea: work backwards from the query q:
to prove q by BC,
check if q is known
already, or
prove by BC all premises of some rule
concluding q
Avoid loops: check if new
subgoal is already on the goal stack
Avoid repeated work: check if new
subgoal
1.has already been proved true, or
2.has already failed