TRS: { fib(N) -> sel(N, fib1(s(0()), s(0()))), fib1(X, Y) -> cons(X, n__fib1(Y, add(X, Y))), add(0(), X) -> X, add(s(X), Y) -> s(add(X, Y)), sel(0(), cons(X, XS)) -> X, sel(s(N), cons(X, XS)) -> sel(N, activate(XS)), fib1(X1, X2) -> n__fib1(X1, X2), activate(n__fib1(X1, X2)) -> fib1(X1, X2), activate(X) -> X} Fail