YES Problem: g(c(x1)) -> g(f(c(x1))) g(f(c(x1))) -> g(f(f(c(x1)))) g(g(x1)) -> g(f(g(x1))) f(f(g(x1))) -> g(f(x1)) Proof: Arctic Interpretation Processor: dimension: 2 interpretation: [0 -&] [f](x0) = [0 -&]x0, [0 0 ] [g](x0) = [-& -&]x0, [0 -&] [c](x0) = [1 0 ]x0 orientation: [1 0 ] [0 -&] g(c(x1)) = [-& -&]x1 >= [-& -&]x1 = g(f(c(x1))) [0 -&] [0 -&] g(f(c(x1))) = [-& -&]x1 >= [-& -&]x1 = g(f(f(c(x1)))) [0 0 ] [0 0 ] g(g(x1)) = [-& -&]x1 >= [-& -&]x1 = g(f(g(x1))) [0 0] [0 -&] f(f(g(x1))) = [0 0]x1 >= [-& -&]x1 = g(f(x1)) problem: g(f(c(x1))) -> g(f(f(c(x1)))) g(g(x1)) -> g(f(g(x1))) f(f(g(x1))) -> g(f(x1)) String Reversal Processor: c(f(g(x1))) -> c(f(f(g(x1)))) g(g(x1)) -> g(f(g(x1))) g(f(f(x1))) -> f(g(x1)) Matrix Interpretation Processor: dim=3 interpretation: [1 0 0] [0] [f](x0) = [0 0 1]x0 + [1] [0 1 0] [0], [1 0 1] [g](x0) = [0 0 1]x0 [0 0 1] , [1 0 0] [c](x0) = [0 0 0]x0 [0 1 0] orientation: [1 0 1] [0] [1 0 1] [0] c(f(g(x1))) = [0 0 0]x1 + [0] >= [0 0 0]x1 + [0] = c(f(f(g(x1)))) [0 0 1] [1] [0 0 1] [1] [1 0 2] [1 0 2] g(g(x1)) = [0 0 1]x1 >= [0 0 1]x1 = g(f(g(x1))) [0 0 1] [0 0 1] [1 0 1] [1] [1 0 1] [0] g(f(f(x1))) = [0 0 1]x1 + [1] >= [0 0 1]x1 + [1] = f(g(x1)) [0 0 1] [1] [0 0 1] [0] problem: c(f(g(x1))) -> c(f(f(g(x1)))) g(g(x1)) -> g(f(g(x1))) Arctic Interpretation Processor: dimension: 2 interpretation: [0 0 ] [f](x0) = [-& -&]x0, [0 1] [g](x0) = [0 1]x0, [0 0 ] [c](x0) = [-& 2 ]x0 orientation: [0 1 ] [0 1 ] c(f(g(x1))) = [-& -&]x1 >= [-& -&]x1 = c(f(f(g(x1)))) [1 2] [0 1] g(g(x1)) = [1 2]x1 >= [0 1]x1 = g(f(g(x1))) problem: c(f(g(x1))) -> c(f(f(g(x1)))) String Reversal Processor: g(f(c(x1))) -> g(f(f(c(x1)))) Bounds Processor: bound: 1 enrichment: match automaton: final states: {4} transitions: g1(13) -> 14* f1(12) -> 13* f1(11) -> 12* c1(10) -> 11* g0(4) -> 4* f0(4) -> 4* c0(4) -> 4* 4 -> 10* 14 -> 4* problem: Qed