NO Problem: zeros() -> cons(0(),n__zeros()) U11(tt(),L) -> U12(tt(),activate(L)) U12(tt(),L) -> s(length(activate(L))) length(nil()) -> 0() length(cons(N,L)) -> U11(tt(),activate(L)) zeros() -> n__zeros() activate(n__zeros()) -> zeros() activate(X) -> X Proof: Matrix Interpretation Processor: dim=3 interpretation: [0] [tt] = [0] [0], [1 1 1] [length](x0) = [0 0 0]x0 [1 0 0] , [0] [0] = [0] [0], [1 0 0] [1 0 0] [cons](x0, x1) = [0 0 0]x0 + [0 0 1]x1 [0 0 0] [0 1 0] , [1 0 0] [1 1 1] [U11](x0, x1) = [0 0 0]x0 + [0 0 0]x1 [0 0 0] [0 0 0] , [1] [nil] = [0] [0], [1] [zeros] = [1] [1], [1 0 0] [1 1 1] [U12](x0, x1) = [0 0 0]x0 + [0 0 0]x1 [0 0 0] [0 0 0] , [1 0 0] [s](x0) = [0 0 0]x0 [0 0 0] , [activate](x0) = x0 , [1] [n__zeros] = [1] [1] orientation: [1] [1] zeros() = [1] >= [1] = cons(0(),n__zeros()) [1] [1] [1 1 1] [1 1 1] U11(tt(),L) = [0 0 0]L >= [0 0 0]L = U12(tt(),activate(L)) [0 0 0] [0 0 0] [1 1 1] [1 1 1] U12(tt(),L) = [0 0 0]L >= [0 0 0]L = s(length(activate(L))) [0 0 0] [0 0 0] [1] [0] length(nil()) = [0] >= [0] = 0() [1] [0] [1 1 1] [1 0 0] [1 1 1] length(cons(N,L)) = [0 0 0]L + [0 0 0]N >= [0 0 0]L = U11(tt(),activate(L)) [1 0 0] [1 0 0] [0 0 0] [1] [1] zeros() = [1] >= [1] = n__zeros() [1] [1] [1] [1] activate(n__zeros()) = [1] >= [1] = zeros() [1] [1] activate(X) = X >= X = X problem: zeros() -> cons(0(),n__zeros()) U11(tt(),L) -> U12(tt(),activate(L)) U12(tt(),L) -> s(length(activate(L))) length(cons(N,L)) -> U11(tt(),activate(L)) zeros() -> n__zeros() activate(n__zeros()) -> zeros() activate(X) -> X Unfolding Processor: loop length: 7 terms: U11(tt(),n__zeros()) U12(tt(),activate(n__zeros())) s(length(activate(activate(n__zeros())))) s(length(activate(n__zeros()))) s(length(zeros())) s(length(cons(0(),n__zeros()))) s(U11(tt(),activate(n__zeros()))) context: s([]) substitution: Qed