MAYBE ignored inputs: (COMMENT rules to obtain PNF of first-order formulas with additional rules ) (COMMENT Example 44 [ FG07 , doi:10.1016/j.ic.2006.12.002 ] ) NRS: [ (0): a#P |- (and <[]P,(forall [a][]Q)>) -> (forall [a](and <[]P,[]Q>)), (1): a#P |- (and <(forall [a][]Q),[]P>) -> (forall [a](and <[]Q,[]P>)), (2): a#P |- (or <[]P,(forall [a][]Q)>) -> (forall [a](or <[]P,[]Q>)), (3): a#P |- (or <(forall [a][]Q),[]P>) -> (forall [a](or <[]Q,[]P>)), (4): a#P |- (and <[]P,(exists [a][]Q)>) -> (exists [a](and <[]P,[]Q>)), (5): a#P |- (and <(exists [a][]Q),[]P>) -> (exists [a](and <[]Q,[]P>)), (6): a#P |- (or <[]P,(exists [a][]Q)>) -> (exists [a](or <[]P,[]Q>)), (7): a#P |- (or <(exists [a][]Q),[]P>) -> (exists [a](or <[]Q,[]P>)), (8): |- (not <(exists [a][]Q)>) -> (forall [a](not []Q)), (9): |- (not <(forall [a][]Q)>) -> (exists [a](not []Q)), (10): a#X |- (forall [a][]X) -> []X, (11): |- (and <(forall [a][]X),(forall [a][]Y)>) -> (forall [a](and <[]X,[]Y>)), (12): a#X |- (exists [a][]X) -> []X, (13): |- (or <(exists [a][]X),(exists [a][]Y)>) -> (exists [a](or <[]X,[]Y>)) ] Check confluence by orthogonality abstract skeleton preserving left-linear check proper overlapping a proper overlap exists 0-1 |- < (forall [a](and <(forall [a][]Q_1),[]Q>)) <= (and <(forall [a][]Q_1),(forall [a][]Q)>) => (forall [a](and <[]Q_1,(forall [a][]Q)>)) > found proper overlaps result: MAYBE time: 5 msec.