Inference and Resolution Questions and Answers

Answer: A

Adding a symmetry breaking constraint, or using a system such as cutting planes that has short proofs where resolution does not, changes the problem the solver faces. Waiting is hopeless against an exponential, other methods may succeed, and shrinking the instance avoids the question. Changing the formulation when the method is provably inadequate, rather than persisting with it, is the same lesson that reformulation teaches in ordinary search.

Answer: B

Where permuting objects gives an equivalent assignment, the solver would otherwise explore every permutation, and an ordering constraint keeps only one representative. Pigeonhole formulas are the classic case. Variable counts rise slightly, the clause structure is unchanged, and satisfiability is preserved rather than created. Recognising that a search is repeating equivalent work, and forbidding the repetitions, is a saving available in every symmetric problem.