YES O(n^3) TRS: { f(0()) -> cons(0()), f(s(0())) -> f(p(s(0()))), p(s(0())) -> 0()} DUP: We consider a non-duplicating system. Trs: { f(0()) -> cons(0()), f(s(0())) -> f(p(s(0()))), p(s(0())) -> 0()} Matrix Interpretation: Interpretation class: triangular [X2] [1 0 1][X2] [0] [s]([X1]) = [0 1 0][X1] + [0] [X0] [0 0 1][X0] [1] [X2] [1 0 0][X2] [0] [p]([X1]) = [0 1 0][X1] + [0] [X0] [0 0 0][X0] [1] [X2] [1 1 1][X2] [1] [f]([X1]) = [0 0 0][X1] + [0] [X0] [0 0 0][X0] [1] [1] [0] = [1] [1] [X2] [1 0 0][X2] [0] [cons]([X1]) = [0 0 0][X1] + [0] [X0] [0 0 0][X0] [0] Qed