TRS: { dbl(0()) -> 0(), dbl(s(X)) -> s(s(dbl(X))), dbls(nil()) -> nil(), dbls(cons(X, Y)) -> cons(dbl(X), dbls(Y)), sel(0(), cons(X, Y)) -> X, sel(s(X), cons(Y, Z)) -> sel(X, Z), indx(nil(), X) -> nil(), indx(cons(X, Y), Z) -> cons(sel(X, Z), indx(Y, Z)), from(X) -> cons(X, from(s(X)))} Fail