NO Problem 1: (VAR v_NonEmpty:S X:S Y:S Z:S) (RULES f(X:S) -> cons(X:S) g(0) -> s(0) g(s(X:S)) -> s(s(g(X:S))) sel(0,cons(X:S)) -> X:S sel(s(X:S),cons(Y:S)) -> sel(X:S,Z:S) ) Problem 1: Extra Variables Processor: -> Rules: f(X:S) -> cons(X:S) g(0) -> s(0) g(s(X:S)) -> s(s(g(X:S))) sel(0,cons(X:S)) -> X:S sel(s(X:S),cons(Y:S)) -> sel(X:S,Z:S) -> The system has extra variables. The problem is infinite.