YES Problem: f(s(X),X) -> f(X,a(X)) f(X,c(X)) -> f(s(X),X) f(X,X) -> c(X) Proof: Matrix Interpretation Processor: dim=1 interpretation: [c](x0) = 2x0, [a](x0) = 2x0, [f](x0, x1) = x0 + x1 + 3, [s](x0) = 2x0 orientation: f(s(X),X) = 3X + 3 >= 3X + 3 = f(X,a(X)) f(X,c(X)) = 3X + 3 >= 3X + 3 = f(s(X),X) f(X,X) = 2X + 3 >= 2X = c(X) problem: f(s(X),X) -> f(X,a(X)) f(X,c(X)) -> f(s(X),X) Matrix Interpretation Processor: dim=1 interpretation: [c](x0) = x0 + 1, [a](x0) = x0, [f](x0, x1) = x0 + x1 + 2, [s](x0) = x0 orientation: f(s(X),X) = 2X + 2 >= 2X + 2 = f(X,a(X)) f(X,c(X)) = 2X + 3 >= 2X + 2 = f(s(X),X) problem: f(s(X),X) -> f(X,a(X)) Matrix Interpretation Processor: dim=1 interpretation: [a](x0) = x0 + 1, [f](x0, x1) = x0 + x1 + 1, [s](x0) = x0 + 2 orientation: f(s(X),X) = 2X + 3 >= 2X + 2 = f(X,a(X)) problem: Qed