MAYBE MAYBE TRS: { a__zeros() -> cons(0(), zeros()), a__zeros() -> zeros(), mark(cons(X1, X2)) -> cons(mark(X1), X2), mark(0()) -> 0(), mark(zeros()) -> a__zeros(), mark(tt()) -> tt(), mark(nil()) -> nil(), mark(s(X)) -> s(mark(X)), mark(and(X1, X2)) -> a__and(mark(X1), X2), mark(length(X)) -> a__length(mark(X)), a__and(X1, X2) -> and(X1, X2), a__and(tt(), X) -> mark(X), a__length(X) -> length(X), a__length(cons(N, L)) -> s(a__length(mark(L))), a__length(nil()) -> 0() } DUP: We consider a non-duplicating system. Trs: { a__zeros() -> cons(0(), zeros()), a__zeros() -> zeros(), mark(cons(X1, X2)) -> cons(mark(X1), X2), mark(0()) -> 0(), mark(zeros()) -> a__zeros(), mark(tt()) -> tt(), mark(nil()) -> nil(), mark(s(X)) -> s(mark(X)), mark(and(X1, X2)) -> a__and(mark(X1), X2), mark(length(X)) -> a__length(mark(X)), a__and(X1, X2) -> and(X1, X2), a__and(tt(), X) -> mark(X), a__length(X) -> length(X), a__length(cons(N, L)) -> s(a__length(mark(L))), a__length(nil()) -> 0() } Fail