YES(?,O(n^3)) Problem: f(1()) -> f(g(1())) f(f(x)) -> f(x) g(0()) -> g(f(0())) g(g(x)) -> g(x) Proof: Matrix Interpretation Processor: dimension: 3 interpretation: [0] [0] = [2] [3], [1 0 4] [0] [g](x0) = [0 0 0]x0 + [0] [0 0 0] [2], [1 1 0] [0] [f](x0) = [0 0 0]x0 + [4] [0 0 0] [2], [0] [1] = [1] [0] orientation: [1] [0] f(1()) = [4] >= [4] = f(g(1())) [2] [2] [1 1 0] [4] [1 1 0] [0] f(f(x)) = [0 0 0]x + [4] >= [0 0 0]x + [4] = f(x) [0 0 0] [2] [0 0 0] [2] [12] [10] g(0()) = [0 ] >= [0 ] = g(f(0())) [2 ] [2 ] [1 0 4] [8] [1 0 4] [0] g(g(x)) = [0 0 0]x + [0] >= [0 0 0]x + [0] = g(x) [0 0 0] [2] [0 0 0] [2] problem: Qed