YES Problem: a__f(f(a())) -> c(f(g(f(a())))) mark(f(X)) -> a__f(mark(X)) mark(a()) -> a() mark(c(X)) -> c(X) mark(g(X)) -> g(mark(X)) a__f(X) -> f(X) Proof: Matrix Interpretation Processor: dim=3 interpretation: [1 0 0] [c](x0) = [0 0 0]x0 [0 0 0] , [1 0 0] [0] [f](x0) = [0 0 0]x0 + [1] [0 1 1] [0], [g](x0) = x0 , [1 1 1] [0] [mark](x0) = [0 1 0]x0 + [0] [0 0 1] [1], [0] [a] = [0] [0], [1 0 0] [1] [a__f](x0) = [0 0 0]x0 + [1] [0 1 1] [0] orientation: [1] [0] a__f(f(a())) = [1] >= [0] = c(f(g(f(a())))) [1] [0] [1 1 1] [1] [1 1 1] [1] mark(f(X)) = [0 0 0]X + [1] >= [0 0 0]X + [1] = a__f(mark(X)) [0 1 1] [1] [0 1 1] [1] [0] [0] mark(a()) = [0] >= [0] = a() [1] [0] [1 0 0] [0] [1 0 0] mark(c(X)) = [0 0 0]X + [0] >= [0 0 0]X = c(X) [0 0 0] [1] [0 0 0] [1 1 1] [0] [1 1 1] [0] mark(g(X)) = [0 1 0]X + [0] >= [0 1 0]X + [0] = g(mark(X)) [0 0 1] [1] [0 0 1] [1] [1 0 0] [1] [1 0 0] [0] a__f(X) = [0 0 0]X + [1] >= [0 0 0]X + [1] = f(X) [0 1 1] [0] [0 1 1] [0] problem: mark(f(X)) -> a__f(mark(X)) mark(a()) -> a() mark(c(X)) -> c(X) mark(g(X)) -> g(mark(X)) Matrix Interpretation Processor: dim=1 interpretation: [c](x0) = x0, [f](x0) = 4x0, [g](x0) = 4x0 + 1, [mark](x0) = 2x0, [a] = 0, [a__f](x0) = 4x0 orientation: mark(f(X)) = 8X >= 8X = a__f(mark(X)) mark(a()) = 0 >= 0 = a() mark(c(X)) = 2X >= X = c(X) mark(g(X)) = 8X + 2 >= 8X + 1 = g(mark(X)) problem: mark(f(X)) -> a__f(mark(X)) mark(a()) -> a() mark(c(X)) -> c(X) Matrix Interpretation Processor: dim=3 interpretation: [1 0 0] [0] [c](x0) = [0 0 1]x0 + [0] [0 0 0] [1], [1 0 0] [1] [f](x0) = [0 0 0]x0 + [0] [0 0 1] [0], [1 0 1] [mark](x0) = [0 1 0]x0 [0 0 1] , [0] [a] = [0] [1], [1 0 0] [a__f](x0) = [0 0 0]x0 [0 0 1] orientation: [1 0 1] [1] [1 0 1] mark(f(X)) = [0 0 0]X + [0] >= [0 0 0]X = a__f(mark(X)) [0 0 1] [0] [0 0 1] [1] [0] mark(a()) = [0] >= [0] = a() [1] [1] [1 0 0] [1] [1 0 0] [0] mark(c(X)) = [0 0 1]X + [0] >= [0 0 1]X + [0] = c(X) [0 0 0] [1] [0 0 0] [1] problem: Qed