YES Problem: f(c(X,s(Y))) -> f(c(s(X),Y)) g(c(s(X),Y)) -> f(c(X,s(Y))) Proof: Matrix Interpretation Processor: dim=3 interpretation: [1 0 0] [1 0 1] [c](x0, x1) = [0 0 0]x0 + [0 0 0]x1 [0 0 0] [0 1 0] , [1 0 0] [1] [g](x0) = [0 0 0]x0 + [0] [0 0 0] [0], [1 0 0] [0] [s](x0) = [0 0 1]x0 + [0] [0 0 1] [1], [1 0 0] [f](x0) = [0 0 0]x0 [0 0 0] orientation: [1 0 0] [1 0 1] [1] [1 0 0] [1 0 1] f(c(X,s(Y))) = [0 0 0]X + [0 0 0]Y + [0] >= [0 0 0]X + [0 0 0]Y = f(c(s(X),Y)) [0 0 0] [0 0 0] [0] [0 0 0] [0 0 0] [1 0 0] [1 0 1] [1] [1 0 0] [1 0 1] [1] g(c(s(X),Y)) = [0 0 0]X + [0 0 0]Y + [0] >= [0 0 0]X + [0 0 0]Y + [0] = f(c(X,s(Y))) [0 0 0] [0 0 0] [0] [0 0 0] [0 0 0] [0] problem: g(c(s(X),Y)) -> f(c(X,s(Y))) Matrix Interpretation Processor: dim=3 interpretation: [1 0 0] [1 0 0] [c](x0, x1) = [0 0 0]x0 + [0 0 0]x1 [0 0 0] [0 0 0] , [1 0 0] [1] [g](x0) = [0 0 0]x0 + [0] [0 0 0] [0], [1 0 0] [s](x0) = [0 0 0]x0 [0 0 0] , [1 0 0] [f](x0) = [0 0 0]x0 [0 0 0] orientation: [1 0 0] [1 0 0] [1] [1 0 0] [1 0 0] g(c(s(X),Y)) = [0 0 0]X + [0 0 0]Y + [0] >= [0 0 0]X + [0 0 0]Y = f(c(X,s(Y))) [0 0 0] [0 0 0] [0] [0 0 0] [0 0 0] problem: Qed