YES(?,O(n^1)) Problem: f(f(x)) -> f(c(f(x))) f(f(x)) -> f(d(f(x))) g(c(x)) -> x g(d(x)) -> x g(c(0())) -> g(d(1())) g(c(1())) -> g(d(0())) Proof: Bounds Processor: bound: 2 enrichment: match automaton: final states: {7} transitions: g1(23) -> 24* d1(22) -> 23* d1(16) -> 17* 01() -> 25* 11() -> 22* f1(12) -> 13* f1(14) -> 15* c1(13) -> 14* f2(30) -> 31* f2(32) -> 33* f0(7) -> 7* d2(50) -> 51* d2(38) -> 39* c0(7) -> 7* c2(31) -> 32* c2(43) -> 44* d0(7) -> 7* g0(7) -> 7* 00() -> 7* 10() -> 7* 7 -> 12* 13 -> 16* 14 -> 30* 15 -> 13,16,7 17 -> 14* 22 -> 24,7 24 -> 7* 25 -> 22* 31 -> 38* 33 -> 50,43,13,7,12,16 39 -> 32* 44 -> 32* 51 -> 32* problem: Qed