MAYBE MAYBE TRS: { cons(X1, X2) -> n__cons(X1, X2), 0() -> n__0(), zeros() -> cons(0(), n__zeros()), zeros() -> n__zeros(), s(X) -> n__s(X), length(X) -> n__length(X), length(cons(N, L)) -> U11(and(isNatList(activate(L)), n__isNat(N)), activate(L)), length(nil()) -> 0(), activate(X) -> X, activate(n__zeros()) -> zeros(), activate(n__take(X1, X2)) -> take(X1, X2), activate(n__0()) -> 0(), activate(n__length(X)) -> length(X), activate(n__s(X)) -> s(X), activate(n__isNatIList(X)) -> isNatIList(X), activate(n__cons(X1, X2)) -> cons(X1, X2), activate(n__nil()) -> nil(), activate(n__isNatList(X)) -> isNatList(X), activate(n__isNat(X)) -> isNat(X), activate(n__and(X1, X2)) -> and(X1, X2), U11(tt(), L) -> s(length(activate(L))), nil() -> n__nil(), U21(tt()) -> nil(), U31(tt(), IL, M, N) -> cons(activate(N), n__take(activate(M), activate(IL))), and(X1, X2) -> n__and(X1, X2), and(tt(), X) -> activate(X), isNat(X) -> n__isNat(X), isNat(n__0()) -> tt(), isNat(n__length(V1)) -> isNatList(activate(V1)), isNat(n__s(V1)) -> isNat(activate(V1)), isNatList(X) -> n__isNatList(X), isNatList(n__take(V1, V2)) -> and(isNat(activate(V1)), n__isNatIList(activate(V2))), isNatList(n__cons(V1, V2)) -> and(isNat(activate(V1)), n__isNatList(activate(V2))), isNatList(n__nil()) -> tt(), isNatIList(X) -> n__isNatIList(X), isNatIList(V) -> isNatList(activate(V)), isNatIList(n__zeros()) -> tt(), isNatIList(n__cons(V1, V2)) -> and(isNat(activate(V1)), n__isNatIList(activate(V2))), take(X1, X2) -> n__take(X1, X2), take(0(), IL) -> U21(isNatIList(IL)), take(s(M), cons(N, IL)) -> U31( and(isNatIList(activate(IL)), n__and(isNat(M), n__isNat(N))), activate(IL), M, N ) } DUP: We consider a duplicating system. Trs: { cons(X1, X2) -> n__cons(X1, X2), 0() -> n__0(), zeros() -> cons(0(), n__zeros()), zeros() -> n__zeros(), s(X) -> n__s(X), length(X) -> n__length(X), length(cons(N, L)) -> U11(and(isNatList(activate(L)), n__isNat(N)), activate(L)), length(nil()) -> 0(), activate(X) -> X, activate(n__zeros()) -> zeros(), activate(n__take(X1, X2)) -> take(X1, X2), activate(n__0()) -> 0(), activate(n__length(X)) -> length(X), activate(n__s(X)) -> s(X), activate(n__isNatIList(X)) -> isNatIList(X), activate(n__cons(X1, X2)) -> cons(X1, X2), activate(n__nil()) -> nil(), activate(n__isNatList(X)) -> isNatList(X), activate(n__isNat(X)) -> isNat(X), activate(n__and(X1, X2)) -> and(X1, X2), U11(tt(), L) -> s(length(activate(L))), nil() -> n__nil(), U21(tt()) -> nil(), U31(tt(), IL, M, N) -> cons(activate(N), n__take(activate(M), activate(IL))), and(X1, X2) -> n__and(X1, X2), and(tt(), X) -> activate(X), isNat(X) -> n__isNat(X), isNat(n__0()) -> tt(), isNat(n__length(V1)) -> isNatList(activate(V1)), isNat(n__s(V1)) -> isNat(activate(V1)), isNatList(X) -> n__isNatList(X), isNatList(n__take(V1, V2)) -> and(isNat(activate(V1)), n__isNatIList(activate(V2))), isNatList(n__cons(V1, V2)) -> and(isNat(activate(V1)), n__isNatList(activate(V2))), isNatList(n__nil()) -> tt(), isNatIList(X) -> n__isNatIList(X), isNatIList(V) -> isNatList(activate(V)), isNatIList(n__zeros()) -> tt(), isNatIList(n__cons(V1, V2)) -> and(isNat(activate(V1)), n__isNatIList(activate(V2))), take(X1, X2) -> n__take(X1, X2), take(0(), IL) -> U21(isNatIList(IL)), take(s(M), cons(N, IL)) -> U31( and(isNatIList(activate(IL)), n__and(isNat(M), n__isNat(N))), activate(IL), M, N ) } Fail