YES O(n^2) TRS: {w(r(x)) -> r(w(x)), b(r(x)) -> r(b(x)), b(w(x)) -> w(b(x))} DUP: We consider a non-duplicating system. Trs: {w(r(x)) -> r(w(x)), b(r(x)) -> r(b(x)), b(w(x)) -> w(b(x))} Matrix Interpretation: Interpretation class: triangular [X1] [1 1][X1] [0] [b]([X0]) = [0 1][X0] + [0] [X1] [1 1][X1] [1] [w]([X0]) = [0 1][X0] + [1] [X1] [1 0][X1] [1] [r]([X0]) = [0 1][X0] + [1] Qed