YES Problem: strict: a() -> b() weak: f(s(x)) -> c(x,f(x)) c(x,c(y(),z())) -> c(y(),c(x,z())) Proof: Matrix Interpretation Processor: dim=5 interpretation: [1 0 0 0 0] [1 0 0 0 1] [0] [1 0 0 0 0] [0 1 0 0 1] [0] [c](x0, x1) = [0 1 1 0 0]x0 + [0 0 1 0 0]x1 + [0] [0 1 1 0 0] [0 0 1 0 0] [1] [0 0 0 0 0] [0 0 0 0 0] [0], [0] [0] [b] = [0] [0] [0], [1 0 1 0 0] [1 1 1 1 0] [f](x0) = [0 0 0 1 0]x0 [1 1 1 0 1] [0 0 0 1 0] , [0] [1] [y] = [1] [0] [0], [1] [0] [a] = [0] [0] [1], [1] [1] [z] = [0] [0] [1], [1 0 1 0 1] [0] [0 1 0 1 0] [0] [s](x0) = [1 1 1 1 0]x0 + [0] [0 1 1 1 1] [0] [0 0 0 0 0] [1] orientation: [1] [0] [0] [0] a() = [0] >= [0] = b() [0] [0] [1] [0] [2 1 2 1 1] [0] [2 0 1 1 0] [0] [2 3 3 3 2] [0] [2 1 1 2 0] [0] f(s(x)) = [0 1 1 1 1]x + [0] >= [0 1 1 1 0]x + [0] = c(x,f(x)) [2 2 2 2 1] [1] [0 1 1 1 0] [1] [0 1 1 1 1] [0] [0 0 0 0 0] [0] [1 0 0 0 0] [2] [1 0 0 0 0] [2] [1 0 0 0 0] [2] [1 0 0 0 0] [2] c(x,c(y(),z())) = [0 1 1 0 0]x + [2] >= [0 1 1 0 0]x + [2] = c(y(),c(x,z())) [0 1 1 0 0] [3] [0 1 1 0 0] [3] [0 0 0 0 0] [0] [0 0 0 0 0] [0] problem: strict: weak: f(s(x)) -> c(x,f(x)) c(x,c(y(),z())) -> c(y(),c(x,z())) Qed