MAYBE MAYBE TRS: { f(X) -> cons(X), g(s(X)) -> s(s(g(X))), g(0()) -> s(0()), sel(s(X), cons(Y)) -> sel(X, Z), sel(0(), cons(X)) -> X } DUP: We consider a duplicating system. Trs: { f(X) -> cons(X), g(s(X)) -> s(s(g(X))), g(0()) -> s(0()), sel(s(X), cons(Y)) -> sel(X, Z), sel(0(), cons(X)) -> X } Fail