Problem: H(H(x)) -> K(x) H(K(x)) -> K(H(x)) Proof: AT confluence processor Complete TRS T' of input TRS: H(H(x)) -> K(x) H(K(x)) -> K(H(x)) T' = (P union S) with TRS P: TRS S:H(H(x)) -> K(x) H(K(x)) -> K(H(x)) S is left-linear and P is reversible. CP(S,S) = H(K(x19)) = K(H(x19)), H(K(H(x20))) = K(K(x20)) CP(S,P union P^-1) = PCP_in(P union P^-1,S) = We have to check termination of S: Matrix Interpretation Processor: dim=1 interpretation: [K](x0) = 4x0 + 6, [H](x0) = 5x0 + 1 orientation: H(H(x)) = 25x + 6 >= 4x + 6 = K(x) H(K(x)) = 20x + 31 >= 20x + 10 = K(H(x)) problem: H(H(x)) -> K(x) Matrix Interpretation Processor: dim=1 interpretation: [K](x0) = 4x0, [H](x0) = 2x0 + 1 orientation: H(H(x)) = 4x + 3 >= 4x = K(x) problem: Qed