YES Problem: W(B(x)) -> B(x) W(W(x)) -> W(x) B(I(x)) -> W(x) Proof: Church Rosser Transformation Processor (critical pair closing system, Thm 2.4): W(W(x22)) -> W(x22) B(I(x23)) -> W(x23) critical peaks: joinable Matrix Interpretation Processor: dim=1 interpretation: [W](x0) = x0, [B](x0) = x0 + 1, [I](x0) = x0 + 6 orientation: W(W(x22)) = x22 >= x22 = W(x22) B(I(x23)) = x23 + 7 >= x23 = W(x23) problem: W(W(x22)) -> W(x22) Matrix Interpretation Processor: dim=1 interpretation: [W](x0) = 2x0 + 5 orientation: W(W(x22)) = 4x22 + 15 >= 2x22 + 5 = W(x22) problem: Qed