Problem: 2nd(cons(X)) -> 2nd(cons1(X,X1)) 2nd(cons1(X,cons(Y))) -> Y from(X) -> cons(X) Proof: Fresh Variable Processor: loop length: 1 terms: 2nd(cons(X)) context: 2nd(cons1(X,[])) substitution: X1 -> 2nd(cons(X)) Qed