Problem: from(X) -> cons(X,from(s(X))) sel(0(),cons(X,XS)) -> X sel(s(N),cons(X,XS)) -> sel(N,XS) minus(X,0()) -> 0() minus(s(X),s(Y)) -> minus(X,Y) quot(0(),s(Y)) -> 0() quot(s(X),s(Y)) -> s(quot(minus(X,Y),s(Y))) zWquot(XS,nil()) -> nil() zWquot(nil(),XS) -> nil() zWquot(cons(X,XS),cons(Y,YS)) -> cons(quot(X,Y),zWquot(XS,YS)) Proof: Containment Processor: loop length: 1 terms: from(X) context: cons(X,[]) substitution: X -> s(X) Qed