YES Problem: active(c()) -> mark(f(g(c()))) active(f(g(X))) -> mark(g(X)) mark(c()) -> active(c()) mark(f(X)) -> active(f(X)) mark(g(X)) -> active(g(X)) f(mark(X)) -> f(X) f(active(X)) -> f(X) g(mark(X)) -> g(X) g(active(X)) -> g(X) Proof: Matrix Interpretation Processor: dim=3 interpretation: [1 0 1] [0] [mark](x0) = [0 0 0]x0 + [1] [0 0 0] [1], [1 0 1] [0] [f](x0) = [0 0 0]x0 + [1] [0 0 0] [0], [1 0 0] [g](x0) = [0 0 0]x0 [0 0 0] , [1 0 1] [0] [active](x0) = [0 1 1]x0 + [0] [0 0 0] [1], [0] [c] = [0] [1] orientation: [1] [0] active(c()) = [1] >= [1] = mark(f(g(c()))) [1] [1] [1 0 0] [0] [1 0 0] [0] active(f(g(X))) = [0 0 0]X + [1] >= [0 0 0]X + [1] = mark(g(X)) [0 0 0] [1] [0 0 0] [1] [1] [1] mark(c()) = [1] >= [1] = active(c()) [1] [1] [1 0 1] [0] [1 0 1] [0] mark(f(X)) = [0 0 0]X + [1] >= [0 0 0]X + [1] = active(f(X)) [0 0 0] [1] [0 0 0] [1] [1 0 0] [0] [1 0 0] [0] mark(g(X)) = [0 0 0]X + [1] >= [0 0 0]X + [0] = active(g(X)) [0 0 0] [1] [0 0 0] [1] [1 0 1] [1] [1 0 1] [0] f(mark(X)) = [0 0 0]X + [1] >= [0 0 0]X + [1] = f(X) [0 0 0] [0] [0 0 0] [0] [1 0 1] [1] [1 0 1] [0] f(active(X)) = [0 0 0]X + [1] >= [0 0 0]X + [1] = f(X) [0 0 0] [0] [0 0 0] [0] [1 0 1] [1 0 0] g(mark(X)) = [0 0 0]X >= [0 0 0]X = g(X) [0 0 0] [0 0 0] [1 0 1] [1 0 0] g(active(X)) = [0 0 0]X >= [0 0 0]X = g(X) [0 0 0] [0 0 0] problem: active(f(g(X))) -> mark(g(X)) mark(c()) -> active(c()) mark(f(X)) -> active(f(X)) mark(g(X)) -> active(g(X)) g(mark(X)) -> g(X) g(active(X)) -> g(X) Matrix Interpretation Processor: dim=1 interpretation: [mark](x0) = 2x0 + 6, [f](x0) = x0 + 5, [g](x0) = x0 + 2, [active](x0) = 2x0 + 4, [c] = 1 orientation: active(f(g(X))) = 2X + 18 >= 2X + 10 = mark(g(X)) mark(c()) = 8 >= 6 = active(c()) mark(f(X)) = 2X + 16 >= 2X + 14 = active(f(X)) mark(g(X)) = 2X + 10 >= 2X + 8 = active(g(X)) g(mark(X)) = 2X + 8 >= X + 2 = g(X) g(active(X)) = 2X + 6 >= X + 2 = g(X) problem: Qed