YES Problem: a(b(c(a(x1)))) -> b(a(c(b(a(b(x1)))))) a(d(x1)) -> c(x1) a(f(f(x1))) -> g(x1) b(g(x1)) -> g(b(x1)) c(x1) -> f(f(x1)) c(a(c(x1))) -> b(c(a(b(c(x1))))) c(d(x1)) -> a(a(x1)) g(x1) -> c(a(x1)) g(x1) -> d(d(d(d(x1)))) Proof: String Reversal Processor: a(c(b(a(x1)))) -> b(a(b(c(a(b(x1)))))) d(a(x1)) -> c(x1) f(f(a(x1))) -> g(x1) g(b(x1)) -> b(g(x1)) c(x1) -> f(f(x1)) c(a(c(x1))) -> c(b(a(c(b(x1))))) d(c(x1)) -> a(a(x1)) g(x1) -> a(c(x1)) g(x1) -> d(d(d(d(x1)))) Matrix Interpretation Processor: dim=1 interpretation: [f](x0) = x0 + 3, [c](x0) = x0 + 6, [d](x0) = x0 + 2, [g](x0) = x0 + 10, [a](x0) = x0 + 4, [b](x0) = x0 orientation: a(c(b(a(x1)))) = x1 + 14 >= x1 + 14 = b(a(b(c(a(b(x1)))))) d(a(x1)) = x1 + 6 >= x1 + 6 = c(x1) f(f(a(x1))) = x1 + 10 >= x1 + 10 = g(x1) g(b(x1)) = x1 + 10 >= x1 + 10 = b(g(x1)) c(x1) = x1 + 6 >= x1 + 6 = f(f(x1)) c(a(c(x1))) = x1 + 16 >= x1 + 16 = c(b(a(c(b(x1))))) d(c(x1)) = x1 + 8 >= x1 + 8 = a(a(x1)) g(x1) = x1 + 10 >= x1 + 10 = a(c(x1)) g(x1) = x1 + 10 >= x1 + 8 = d(d(d(d(x1)))) problem: a(c(b(a(x1)))) -> b(a(b(c(a(b(x1)))))) d(a(x1)) -> c(x1) f(f(a(x1))) -> g(x1) g(b(x1)) -> b(g(x1)) c(x1) -> f(f(x1)) c(a(c(x1))) -> c(b(a(c(b(x1))))) d(c(x1)) -> a(a(x1)) g(x1) -> a(c(x1)) Matrix Interpretation Processor: dim=1 interpretation: [f](x0) = x0, [c](x0) = x0, [d](x0) = 4x0 + 12, [g](x0) = 2x0 + 4, [a](x0) = 2x0 + 4, [b](x0) = x0 orientation: a(c(b(a(x1)))) = 4x1 + 12 >= 4x1 + 12 = b(a(b(c(a(b(x1)))))) d(a(x1)) = 8x1 + 28 >= x1 = c(x1) f(f(a(x1))) = 2x1 + 4 >= 2x1 + 4 = g(x1) g(b(x1)) = 2x1 + 4 >= 2x1 + 4 = b(g(x1)) c(x1) = x1 >= x1 = f(f(x1)) c(a(c(x1))) = 2x1 + 4 >= 2x1 + 4 = c(b(a(c(b(x1))))) d(c(x1)) = 4x1 + 12 >= 4x1 + 12 = a(a(x1)) g(x1) = 2x1 + 4 >= 2x1 + 4 = a(c(x1)) problem: a(c(b(a(x1)))) -> b(a(b(c(a(b(x1)))))) f(f(a(x1))) -> g(x1) g(b(x1)) -> b(g(x1)) c(x1) -> f(f(x1)) c(a(c(x1))) -> c(b(a(c(b(x1))))) d(c(x1)) -> a(a(x1)) g(x1) -> a(c(x1)) String Reversal Processor: a(b(c(a(x1)))) -> b(a(c(b(a(b(x1)))))) a(f(f(x1))) -> g(x1) b(g(x1)) -> g(b(x1)) c(x1) -> f(f(x1)) c(a(c(x1))) -> b(c(a(b(c(x1))))) c(d(x1)) -> a(a(x1)) g(x1) -> c(a(x1)) Matrix Interpretation Processor: dim=1 interpretation: [f](x0) = x0, [c](x0) = x0, [d](x0) = 10x0 + 8, [g](x0) = x0, [a](x0) = x0, [b](x0) = x0 orientation: a(b(c(a(x1)))) = x1 >= x1 = b(a(c(b(a(b(x1)))))) a(f(f(x1))) = x1 >= x1 = g(x1) b(g(x1)) = x1 >= x1 = g(b(x1)) c(x1) = x1 >= x1 = f(f(x1)) c(a(c(x1))) = x1 >= x1 = b(c(a(b(c(x1))))) c(d(x1)) = 10x1 + 8 >= x1 = a(a(x1)) g(x1) = x1 >= x1 = c(a(x1)) problem: a(b(c(a(x1)))) -> b(a(c(b(a(b(x1)))))) a(f(f(x1))) -> g(x1) b(g(x1)) -> g(b(x1)) c(x1) -> f(f(x1)) c(a(c(x1))) -> b(c(a(b(c(x1))))) g(x1) -> c(a(x1)) Matrix Interpretation Processor: dim=1 interpretation: [f](x0) = x0 + 1, [c](x0) = x0 + 4, [g](x0) = 4x0 + 9, [a](x0) = 4x0 + 1, [b](x0) = x0 orientation: a(b(c(a(x1)))) = 16x1 + 21 >= 16x1 + 21 = b(a(c(b(a(b(x1)))))) a(f(f(x1))) = 4x1 + 9 >= 4x1 + 9 = g(x1) b(g(x1)) = 4x1 + 9 >= 4x1 + 9 = g(b(x1)) c(x1) = x1 + 4 >= x1 + 2 = f(f(x1)) c(a(c(x1))) = 4x1 + 21 >= 4x1 + 21 = b(c(a(b(c(x1))))) g(x1) = 4x1 + 9 >= 4x1 + 5 = c(a(x1)) problem: a(b(c(a(x1)))) -> b(a(c(b(a(b(x1)))))) a(f(f(x1))) -> g(x1) b(g(x1)) -> g(b(x1)) c(a(c(x1))) -> b(c(a(b(c(x1))))) String Reversal Processor: a(c(b(a(x1)))) -> b(a(b(c(a(b(x1)))))) f(f(a(x1))) -> g(x1) g(b(x1)) -> b(g(x1)) c(a(c(x1))) -> c(b(a(c(b(x1))))) Bounds Processor: bound: 0 enrichment: match automaton: final states: {10,9,8,1} transitions: b0(5) -> 6* b0(12) -> 13* b0(7) -> 1* b0(8) -> 9* b0(2) -> 3* g0(2) -> 8* c0(4) -> 5* c0(13) -> 10* c0(3) -> 11* a0(3) -> 4* a0(6) -> 7* a0(11) -> 12* f60() -> 2* 1 -> 12* 9 -> 8* problem: Qed