NO Problem 1: (VAR v_NonEmpty:S N:S X:S XS:S Y:S) (RULES from(X:S) -> cons(X:S) minus(s(X:S),s(Y:S)) -> minus(X:S,Y:S) minus(X:S,0) -> 0 quot(0,s(Y:S)) -> 0 quot(s(X:S),s(Y:S)) -> s(quot(minus(X:S,Y:S),s(Y:S))) sel(0,cons(X:S)) -> X:S sel(s(N:S),cons(X:S)) -> sel(N:S,XS:S) zWquot(cons(X:S),cons(Y:S)) -> cons(quot(X:S,Y:S)) zWquot(nil,XS:S) -> nil zWquot(XS:S,nil) -> nil ) Problem 1: Extra Variables Processor: -> Rules: from(X:S) -> cons(X:S) minus(s(X:S),s(Y:S)) -> minus(X:S,Y:S) minus(X:S,0) -> 0 quot(0,s(Y:S)) -> 0 quot(s(X:S),s(Y:S)) -> s(quot(minus(X:S,Y:S),s(Y:S))) sel(0,cons(X:S)) -> X:S sel(s(N:S),cons(X:S)) -> sel(N:S,XS:S) zWquot(cons(X:S),cons(Y:S)) -> cons(quot(X:S,Y:S)) zWquot(nil,XS:S) -> nil zWquot(XS:S,nil) -> nil -> The system has extra variables. The problem is infinite.