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