Problem: eq(0(),0()) -> true() eq(s(X),s(Y)) -> eq(X,Y) eq(X,Y) -> false() inf(X) -> cons(X,inf(s(X))) take(0(),X) -> nil() take(s(X),cons(Y,L)) -> cons(Y,take(X,L)) length(nil()) -> 0() length(cons(X,L)) -> s(length(L)) Proof: Containment Processor: loop length: 1 terms: inf(X) context: cons(X,[]) substitution: X -> s(X) Qed