Problem: b(w(x)) -> w(w(w(b(x)))) w(b(x)) -> b(x) b(b(x)) -> w(w(w(w(x)))) w(w(x)) -> w(x) Proof: AT confluence processor Complete TRS T' of input TRS: b(w(x)) -> w(w(w(b(x)))) w(b(x)) -> b(x) b(b(x)) -> w(w(w(w(x)))) w(w(x)) -> w(x) T' = (P union S) with TRS P: TRS S:b(w(x)) -> w(w(w(b(x)))) w(b(x)) -> b(x) b(b(x)) -> w(w(w(w(x)))) w(w(x)) -> w(x) S is left-linear and P is reversible. CP(S,S) = w(w(w(w(b(x73))))) = b(w(x73)), b(w(w(w(b(x74))))) = w(w(w(w(w(x74))))), b(b(x75)) = w(w(w(b(b(x75))))), w(b(x76)) = w(b(x76)), w(w(w(w(w(x77))))) = b(b(x77)), b(w(w(w(w(x78))))) = w(w(w(w(b(x78))))), b(w(x79)) = w(w(w(b(w(x79))))), w(w(x80)) = w(w(x80)) 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: [b](x0) = 2x0 + 1, [w](x0) = x0 orientation: b(w(x)) = 2x + 1 >= 2x + 1 = w(w(w(b(x)))) w(b(x)) = 2x + 1 >= 2x + 1 = b(x) b(b(x)) = 4x + 3 >= x = w(w(w(w(x)))) w(w(x)) = x >= x = w(x) problem: b(w(x)) -> w(w(w(b(x)))) w(b(x)) -> b(x) w(w(x)) -> w(x) Matrix Interpretation Processor: dim=1 interpretation: [b](x0) = 3x0, [w](x0) = x0 + 1 orientation: b(w(x)) = 3x + 3 >= 3x + 3 = w(w(w(b(x)))) w(b(x)) = 3x + 1 >= 3x = b(x) w(w(x)) = x + 2 >= x + 1 = w(x) problem: b(w(x)) -> w(w(w(b(x)))) Matrix Interpretation Processor: dim=1 interpretation: [b](x0) = 4x0 + 3, [w](x0) = x0 + 3 orientation: b(w(x)) = 4x + 15 >= 4x + 12 = w(w(w(b(x)))) problem: Qed