YES Problem: a(b(x)) -> b(b(a(x))) Proof: DP Processor: DPs: a#(b(x)) -> a#(x) TRS: a(b(x)) -> b(b(a(x))) Usable Rule Processor: DPs: a#(b(x)) -> a#(x) TRS: CDG Processor: DPs: a#(b(x)) -> a#(x) TRS: graph: Qed