YES Problem: b(d(b(x1))) -> c(d(b(x1))) b(a(c(x1))) -> b(c(x1)) a(d(x1)) -> d(c(x1)) b(b(b(x1))) -> a(b(c(x1))) d(c(x1)) -> b(d(x1)) d(c(x1)) -> d(b(d(x1))) d(a(c(x1))) -> b(b(x1)) Proof: Arctic Interpretation Processor: dimension: 1 interpretation: [a](x0) = 4x0, [c](x0) = 4x0, [d](x0) = x0, [b](x0) = 4x0 orientation: b(d(b(x1))) = 8x1 >= 8x1 = c(d(b(x1))) b(a(c(x1))) = 12x1 >= 8x1 = b(c(x1)) a(d(x1)) = 4x1 >= 4x1 = d(c(x1)) b(b(b(x1))) = 12x1 >= 12x1 = a(b(c(x1))) d(c(x1)) = 4x1 >= 4x1 = b(d(x1)) d(c(x1)) = 4x1 >= 4x1 = d(b(d(x1))) d(a(c(x1))) = 8x1 >= 8x1 = b(b(x1)) problem: b(d(b(x1))) -> c(d(b(x1))) a(d(x1)) -> d(c(x1)) b(b(b(x1))) -> a(b(c(x1))) d(c(x1)) -> b(d(x1)) d(c(x1)) -> d(b(d(x1))) d(a(c(x1))) -> b(b(x1)) String Reversal Processor: b(d(b(x1))) -> b(d(c(x1))) d(a(x1)) -> c(d(x1)) b(b(b(x1))) -> c(b(a(x1))) c(d(x1)) -> d(b(x1)) c(d(x1)) -> d(b(d(x1))) c(a(d(x1))) -> b(b(x1)) Matrix Interpretation Processor: dim=3 interpretation: [1 0 0] [1] [a](x0) = [1 1 0]x0 + [0] [0 0 1] [1], [1 0 0] [1] [c](x0) = [0 0 0]x0 + [0] [0 0 0] [0], [1 0 1] [d](x0) = [0 1 0]x0 [0 0 0] , [1 0 0] [1] [b](x0) = [0 0 0]x0 + [0] [0 0 0] [0] orientation: [1 0 0] [2] [1 0 0] [2] b(d(b(x1))) = [0 0 0]x1 + [0] >= [0 0 0]x1 + [0] = b(d(c(x1))) [0 0 0] [0] [0 0 0] [0] [1 0 1] [2] [1 0 1] [1] d(a(x1)) = [1 1 0]x1 + [0] >= [0 0 0]x1 + [0] = c(d(x1)) [0 0 0] [0] [0 0 0] [0] [1 0 0] [3] [1 0 0] [3] b(b(b(x1))) = [0 0 0]x1 + [0] >= [0 0 0]x1 + [0] = c(b(a(x1))) [0 0 0] [0] [0 0 0] [0] [1 0 1] [1] [1 0 0] [1] c(d(x1)) = [0 0 0]x1 + [0] >= [0 0 0]x1 + [0] = d(b(x1)) [0 0 0] [0] [0 0 0] [0] [1 0 1] [1] [1 0 1] [1] c(d(x1)) = [0 0 0]x1 + [0] >= [0 0 0]x1 + [0] = d(b(d(x1))) [0 0 0] [0] [0 0 0] [0] [1 0 1] [2] [1 0 0] [2] c(a(d(x1))) = [0 0 0]x1 + [0] >= [0 0 0]x1 + [0] = b(b(x1)) [0 0 0] [0] [0 0 0] [0] problem: b(d(b(x1))) -> b(d(c(x1))) b(b(b(x1))) -> c(b(a(x1))) c(d(x1)) -> d(b(x1)) c(d(x1)) -> d(b(d(x1))) c(a(d(x1))) -> b(b(x1)) String Reversal Processor: b(d(b(x1))) -> c(d(b(x1))) b(b(b(x1))) -> a(b(c(x1))) d(c(x1)) -> b(d(x1)) d(c(x1)) -> d(b(d(x1))) d(a(c(x1))) -> b(b(x1)) Matrix Interpretation Processor: dim=3 interpretation: [1 1 0] [a](x0) = [0 0 0]x0 [0 0 0] , [1 0 0] [0] [c](x0) = [0 0 0]x0 + [1] [0 0 0] [0], [1 0 0] [0] [d](x0) = [0 0 0]x0 + [1] [0 0 0] [1], [1 0 0] [b](x0) = [0 0 1]x0 [0 0 0] orientation: [1 0 0] [0] [1 0 0] [0] b(d(b(x1))) = [0 0 0]x1 + [1] >= [0 0 0]x1 + [1] = c(d(b(x1))) [0 0 0] [0] [0 0 0] [0] [1 0 0] [1 0 0] b(b(b(x1))) = [0 0 0]x1 >= [0 0 0]x1 = a(b(c(x1))) [0 0 0] [0 0 0] [1 0 0] [0] [1 0 0] [0] d(c(x1)) = [0 0 0]x1 + [1] >= [0 0 0]x1 + [1] = b(d(x1)) [0 0 0] [1] [0 0 0] [0] [1 0 0] [0] [1 0 0] [0] d(c(x1)) = [0 0 0]x1 + [1] >= [0 0 0]x1 + [1] = d(b(d(x1))) [0 0 0] [1] [0 0 0] [1] [1 0 0] [1] [1 0 0] d(a(c(x1))) = [0 0 0]x1 + [1] >= [0 0 0]x1 = b(b(x1)) [0 0 0] [1] [0 0 0] problem: b(d(b(x1))) -> c(d(b(x1))) b(b(b(x1))) -> a(b(c(x1))) d(c(x1)) -> b(d(x1)) d(c(x1)) -> d(b(d(x1))) Arctic Interpretation Processor: dimension: 1 interpretation: [a](x0) = 6x0, [c](x0) = 8x0, [d](x0) = x0, [b](x0) = 8x0 orientation: b(d(b(x1))) = 16x1 >= 16x1 = c(d(b(x1))) b(b(b(x1))) = 24x1 >= 22x1 = a(b(c(x1))) d(c(x1)) = 8x1 >= 8x1 = b(d(x1)) d(c(x1)) = 8x1 >= 8x1 = d(b(d(x1))) problem: b(d(b(x1))) -> c(d(b(x1))) d(c(x1)) -> b(d(x1)) d(c(x1)) -> d(b(d(x1))) String Reversal Processor: b(d(b(x1))) -> b(d(c(x1))) c(d(x1)) -> d(b(x1)) c(d(x1)) -> d(b(d(x1))) Matrix Interpretation Processor: dim=3 interpretation: [1 1 1] [0] [c](x0) = [0 0 0]x0 + [0] [0 1 1] [1], [1 0 0] [d](x0) = [0 0 1]x0 [0 1 0] , [1 0 1] [0] [b](x0) = [0 1 1]x0 + [1] [0 0 0] [0] orientation: [1 1 2] [1] [1 1 1] [0] b(d(b(x1))) = [0 1 1]x1 + [2] >= [0 1 1]x1 + [2] = b(d(c(x1))) [0 0 0] [0] [0 0 0] [0] [1 1 1] [0] [1 0 1] [0] c(d(x1)) = [0 0 0]x1 + [0] >= [0 0 0]x1 + [0] = d(b(x1)) [0 1 1] [1] [0 1 1] [1] [1 1 1] [0] [1 1 0] [0] c(d(x1)) = [0 0 0]x1 + [0] >= [0 0 0]x1 + [0] = d(b(d(x1))) [0 1 1] [1] [0 1 1] [1] problem: c(d(x1)) -> d(b(x1)) c(d(x1)) -> d(b(d(x1))) Arctic Interpretation Processor: dimension: 2 interpretation: [1 -&] [c](x0) = [2 3 ]x0, [0 0 ] [d](x0) = [1 -&]x0, [0 0 ] [b](x0) = [0 -&]x0 orientation: [1 1] [0 0] c(d(x1)) = [4 2]x1 >= [1 1]x1 = d(b(x1)) [1 1] [1 0] c(d(x1)) = [4 2]x1 >= [2 1]x1 = d(b(d(x1))) problem: c(d(x1)) -> d(b(d(x1))) Arctic Interpretation Processor: dimension: 3 interpretation: [0 1 1 ] [c](x0) = [0 1 -&]x0 [-& 1 1 ] , [0 -& -&] [d](x0) = [1 0 -&]x0 [0 0 -&] , [0 -& -&] [b](x0) = [-& 0 0 ]x0 [-& 0 -&] orientation: [2 1 -&] [0 -& -&] c(d(x1)) = [2 1 -&]x1 >= [1 0 -&]x1 = d(b(d(x1))) [2 1 -&] [1 0 -&] problem: Qed