How verify this plan answers query?
1. Verify information content of plan
2. Verifying binding pattern constraints
IMDBActor($Actor, M) ? actor-in(M, Part, Actor)
Spot($M, Rev, Y) ? review-of(M, Rev) &
Sidewalk($C, M, Th) ? shows-in(M, C, Th)
plan(M, R, brando, seattle) ? IMDBActor(b, M) &