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: Matrix Interpretation Processor: dim=1 interpretation: [d](x0) = x0, [a](x0) = x0 + 8, [b](x0) = x0 + 8, [c](x0) = x0 + 8 orientation: b(d(b(x1))) = x1 + 16 >= x1 + 16 = c(d(b(x1))) b(a(c(x1))) = x1 + 24 >= x1 + 16 = b(c(x1)) a(d(x1)) = x1 + 8 >= x1 + 8 = d(c(x1)) b(b(b(x1))) = x1 + 24 >= x1 + 24 = a(b(c(x1))) d(c(x1)) = x1 + 8 >= x1 + 8 = b(d(x1)) d(c(x1)) = x1 + 8 >= x1 + 8 = d(b(d(x1))) d(a(c(x1))) = x1 + 16 >= x1 + 16 = 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 1 0] [d](x0) = [0 0 0]x0 [0 0 0] , [1 0 0] [0] [a](x0) = [0 1 0]x0 + [1] [0 0 0] [1], [1 0 0] [b](x0) = [0 0 0]x0 [0 0 0] , [1 0 0] [c](x0) = [0 0 0]x0 [0 0 0] orientation: [1 0 0] [1 0 0] b(d(b(x1))) = [0 0 0]x1 >= [0 0 0]x1 = b(d(c(x1))) [0 0 0] [0 0 0] [1 1 0] [1] [1 1 0] d(a(x1)) = [0 0 0]x1 + [0] >= [0 0 0]x1 = c(d(x1)) [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 = c(b(a(x1))) [0 0 0] [0 0 0] [1 1 0] [1 0 0] c(d(x1)) = [0 0 0]x1 >= [0 0 0]x1 = d(b(x1)) [0 0 0] [0 0 0] [1 1 0] [1 1 0] c(d(x1)) = [0 0 0]x1 >= [0 0 0]x1 = d(b(d(x1))) [0 0 0] [0 0 0] [1 1 0] [1 0 0] c(a(d(x1))) = [0 0 0]x1 >= [0 0 0]x1 = b(b(x1)) [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)) Bounds Processor: bound: 1 enrichment: match automaton: final states: {13,10,8,5,1} transitions: b0(4) -> 1* b0(11) -> 12* b0(9) -> 13* b0(2) -> 9* b0(6) -> 7* c1(14) -> 15* c0(7) -> 5* c0(2) -> 3* d1(15) -> 16* b1(16) -> 17* a0(2) -> 6* f40() -> 2* d0(12) -> 10* d0(2) -> 11* d0(3) -> 4* d0(9) -> 8* 17 -> 1,12,9 13 -> 3* 8 -> 3* 1 -> 9,12 5 -> 9,13 9 -> 14* 10 -> 3* problem: Qed