NO Problem 1: (VAR v_NonEmpty:S X:S) (RULES eq -> eq eq -> ffalse eq -> ttrue inf(X:S) -> cons length(cons) -> s length(nil) -> 0 take(0,X:S) -> nil take(s,cons) -> cons ) Problem 1: Dependency Pairs Processor: -> Pairs: EQ -> EQ -> Rules: eq -> eq eq -> ffalse eq -> ttrue inf(X:S) -> cons length(cons) -> s length(nil) -> 0 take(0,X:S) -> nil take(s,cons) -> cons Problem 1: Infinite Processor: -> Pairs: EQ -> EQ -> Rules: eq -> eq eq -> ffalse eq -> ttrue inf(X:S) -> cons length(cons) -> s length(nil) -> 0 take(0,X:S) -> nil take(s,cons) -> cons -> Pairs in cycle: EQ -> EQ The problem is infinite.