MAYBE MAYBE TRS: { if(true(), X, Y) -> activate(X), if(false(), X, Y) -> activate(Y), zero(0()) -> true(), zero(s(X)) -> false(), fact(X) -> if(zero(X), n__s(0()), n__prod(X, fact(p(X)))), p(s(X)) -> X, add(0(), X) -> X, add(s(X), Y) -> s(add(X, Y)), s(X) -> n__s(X), prod(X1, X2) -> n__prod(X1, X2), prod(0(), X) -> 0(), prod(s(X), Y) -> add(Y, prod(X, Y)), activate(X) -> X, activate(n__s(X)) -> s(X), activate(n__prod(X1, X2)) -> prod(X1, X2) } DUP: We consider a duplicating system. Trs: { if(true(), X, Y) -> activate(X), if(false(), X, Y) -> activate(Y), zero(0()) -> true(), zero(s(X)) -> false(), fact(X) -> if(zero(X), n__s(0()), n__prod(X, fact(p(X)))), p(s(X)) -> X, add(0(), X) -> X, add(s(X), Y) -> s(add(X, Y)), s(X) -> n__s(X), prod(X1, X2) -> n__prod(X1, X2), prod(0(), X) -> 0(), prod(s(X), Y) -> add(Y, prod(X, Y)), activate(X) -> X, activate(n__s(X)) -> s(X), activate(n__prod(X1, X2)) -> prod(X1, X2) } Fail