Problem:
 from(X) -> cons(X,from(s(X)))
 head(cons(X,XS)) -> X
 2nd(cons(X,XS)) -> head(XS)
 take(0(),XS) -> nil()
 take(s(N),cons(X,XS)) -> cons(X,take(N,XS))
 sel(0(),cons(X,XS)) -> X
 sel(s(N),cons(X,XS)) -> sel(N,XS)

Proof:
 Containment Processor: loop length: 1
                        terms:
                         from(X)
                        context: cons(X,[])
                        substitution:
                         X -> s(X)
  Qed