YES O(n^2) TRS: { f(s(X)) -> f(X), g(cons(s(X), Y)) -> s(X), g(cons(0(), Y)) -> g(Y), h(cons(X, Y)) -> h(g(cons(X, Y))) } DUP: We consider a non-duplicating system. Trs: { f(s(X)) -> f(X), g(cons(s(X), Y)) -> s(X), g(cons(0(), Y)) -> g(Y), h(cons(X, Y)) -> h(g(cons(X, Y))) } Matrix Interpretation: Interpretation class: triangular [X1] [1 1][X1] [0] [h]([X0]) = [0 0][X0] + [0] [0] [0] = [0] [X3] [X1] [1 0][X3] [1 0][X1] [1] [cons]([X2], [X0]) = [0 0][X2] + [0 1][X0] + [1] [X1] [1 0][X1] [0] [g]([X0]) = [0 0][X0] + [0] [X1] [1 0][X1] [1] [s]([X0]) = [0 0][X0] + [0] [X1] [1 0][X1] [0] [f]([X0]) = [0 0][X0] + [0] Qed