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)) Arctic Interpretation Processor: dimension: 2 interpretation: [0 2 ] [a](x0) = [-& 1 ]x0, [0 0 ] [c](x0) = [-& -&]x0, [0 0] [d](x0) = [0 0]x0, [0 0 ] [b](x0) = [-& 0 ]x0 orientation: [0 0] [0 0 ] b(d(b(x1))) = [0 0]x1 >= [-& -&]x1 = c(d(b(x1))) [2 2] [0 0] a(d(x1)) = [1 1]x1 >= [0 0]x1 = d(c(x1)) [0 0 ] [0 0 ] b(b(b(x1))) = [-& 0 ]x1 >= [-& -&]x1 = a(b(c(x1))) [0 0] [0 0] d(c(x1)) = [0 0]x1 >= [0 0]x1 = b(d(x1)) [0 0] [0 0] d(c(x1)) = [0 0]x1 >= [0 0]x1 = d(b(d(x1))) [0 0] [0 0 ] d(a(c(x1))) = [0 0]x1 >= [-& 0 ]x1 = b(b(x1)) 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))) d(a(c(x1))) -> b(b(x1)) String Reversal Processor: 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)) Bounds Processor: bound: 1 enrichment: match automaton: final states: {13,10,8,5,1} transitions: f40() -> 2* b0(2) -> 9* b0(9) -> 13* b0(4) -> 1* b0(11) -> 12* b0(6) -> 7* d0(12) -> 10* d0(2) -> 11* d0(9) -> 8* d0(3) -> 4* c0(7) -> 5* c0(2) -> 3* a0(2) -> 6* b1(16) -> 17* d1(15) -> 16* c1(14) -> 15* 1 -> 9,12 5 -> 9,13 8 -> 3* 9 -> 14* 10 -> 3* 13 -> 3* 17 -> 1,12,9 problem: Qed