Problem: a(x1) -> x1 a(b(b(x1))) -> b(b(b(c(a(a(x1)))))) b(c(x1)) -> x1 Proof: Bounds Processor: bound: 0 enrichment: match automaton: final states: {3,2} transitions: a0(1) -> 2* b0(1) -> 3* c0(1) -> 1* 1 -> 3,2 problem: Qed