YES Problem: rec[flip_0][1](E()) -> E() rec[flip_0][1](Z(x1)) -> O(rec[flip_0][1](x1)) rec[flip_0][1](O(x1)) -> Z(rec[flip_0][1](x1)) main(x1) -> rec[flip_0][1](x1) Proof: Matrix Interpretation Processor: dim=1 interpretation: [main](x0) = x0 + 1, [O](x0) = x0, [Z](x0) = x0, [rec[flip_0][1]](x0) = x0, [E] = 0 orientation: rec[flip_0][1](E()) = 0 >= 0 = E() rec[flip_0][1](Z(x1)) = x1 >= x1 = O(rec[flip_0][1](x1)) rec[flip_0][1](O(x1)) = x1 >= x1 = Z(rec[flip_0][1](x1)) main(x1) = x1 + 1 >= x1 = rec[flip_0][1](x1) problem: rec[flip_0][1](E()) -> E() rec[flip_0][1](Z(x1)) -> O(rec[flip_0][1](x1)) rec[flip_0][1](O(x1)) -> Z(rec[flip_0][1](x1)) Matrix Interpretation Processor: dim=3 interpretation: [1 0 0] [0] [O](x0) = [0 0 0]x0 + [0] [0 1 1] [1], [1 0 0] [0] [Z](x0) = [0 0 0]x0 + [0] [0 1 1] [1], [1 1 1] [rec[flip_0][1]](x0) = [0 1 0]x0 [1 0 1] , [0] [E] = [1] [0] orientation: [1] [0] rec[flip_0][1](E()) = [1] >= [1] = E() [0] [0] [1 1 1] [1] [1 1 1] [0] rec[flip_0][1](Z(x1)) = [0 0 0]x1 + [0] >= [0 0 0]x1 + [0] = O(rec[flip_0][1](x1)) [1 1 1] [1] [1 1 1] [1] [1 1 1] [1] [1 1 1] [0] rec[flip_0][1](O(x1)) = [0 0 0]x1 + [0] >= [0 0 0]x1 + [0] = Z(rec[flip_0][1](x1)) [1 1 1] [1] [1 1 1] [1] problem: Qed