YES O(n^2) TRS: { g(ok(X)) -> ok(g(X)), h(mark(X)) -> mark(h(X)), h(ok(X)) -> ok(h(X)), f(mark(X)) -> mark(f(X)), f(ok(X)) -> ok(f(X)), active(h(X)) -> h(active(X)), active(f(X)) -> mark(g(h(f(X)))), active(f(X)) -> f(active(X)), proper(g(X)) -> g(proper(X)), proper(h(X)) -> h(proper(X)), proper(f(X)) -> f(proper(X)), top(mark(X)) -> top(proper(X)), top(ok(X)) -> top(active(X)) } DUP: We consider a non-duplicating system. Trs: { g(ok(X)) -> ok(g(X)), h(mark(X)) -> mark(h(X)), h(ok(X)) -> ok(h(X)), f(mark(X)) -> mark(f(X)), f(ok(X)) -> ok(f(X)), active(h(X)) -> h(active(X)), active(f(X)) -> mark(g(h(f(X)))), active(f(X)) -> f(active(X)), proper(g(X)) -> g(proper(X)), proper(h(X)) -> h(proper(X)), proper(f(X)) -> f(proper(X)), top(mark(X)) -> top(proper(X)), top(ok(X)) -> top(active(X)) } Matrix Interpretation: Interpretation class: triangular [X1] [1 1][X1] [0] [top]([X0]) = [0 1][X0] + [0] [X1] [1 6][X1] [0] [ok]([X0]) = [0 1][X0] + [7] [X1] [1 1][X1] [0] [proper]([X0]) = [0 1][X0] + [0] [X1] [1 6][X1] [0] [active]([X0]) = [0 1][X0] + [5] [X1] [1 6][X1] [0] [f]([X0]) = [0 1][X0] + [6] [X1] [1 1][X1] [0] [h]([X0]) = [0 1][X0] + [1] [X1] [1 1][X1] [0] [g]([X0]) = [0 1][X0] + [1] [X1] [1 2][X1] [0] [mark]([X0]) = [0 1][X0] + [3] Qed