YES(?,O(n^1)) Problem: a(a(b(b(x1)))) -> b(b(b(a(a(a(x1)))))) a(c(x1)) -> c(a(x1)) c(b(x1)) -> b(c(x1)) Proof: Bounds Processor: bound: 1 enrichment: match automaton: final states: {3,2} transitions: b1(8) -> 9* c1(7) -> 8* a0(1) -> 2* b0(1) -> 1* c0(1) -> 3* 1 -> 7* 9 -> 8,3 problem: Qed