YES Problem: d(a(x1)) -> b(d(x1)) b(x1) -> a(a(a(x1))) c(d(c(x1))) -> a(d(x1)) b(d(d(x1))) -> c(c(d(d(c(x1))))) Proof: Matrix Interpretation Processor: dim=1 interpretation: [d](x0) = 3x0, [c](x0) = x0 + 1, [a](x0) = x0 + 4, [b](x0) = x0 + 12 orientation: d(a(x1)) = 3x1 + 12 >= 3x1 + 12 = b(d(x1)) b(x1) = x1 + 12 >= x1 + 12 = a(a(a(x1))) c(d(c(x1))) = 3x1 + 4 >= 3x1 + 4 = a(d(x1)) b(d(d(x1))) = 9x1 + 12 >= 9x1 + 11 = c(c(d(d(c(x1))))) problem: d(a(x1)) -> b(d(x1)) b(x1) -> a(a(a(x1))) c(d(c(x1))) -> a(d(x1)) Bounds Processor: bound: 1 enrichment: match automaton: final states: {7,4,1} transitions: b0(3) -> 1* a0(5) -> 6* a0(6) -> 4* a0(3) -> 7* a0(2) -> 5* a1(13) -> 14* a1(12) -> 13* a1(14) -> 15* f40() -> 2* d0(2) -> 3* 1 -> 3* 3 -> 12* 15 -> 1* problem: Qed