YES O(n^2) TRS: { c(ok(X)) -> ok(c(X)), f(mark(X)) -> mark(f(X)), f(ok(X)) -> ok(f(X)), g(ok(X)) -> ok(g(X)), active(c(X)) -> mark(d(X)), active(f(X)) -> f(active(X)), active(f(f(X))) -> mark(c(f(g(f(X))))), active(h(X)) -> mark(c(d(X))), active(h(X)) -> h(active(X)), d(ok(X)) -> ok(d(X)), h(mark(X)) -> mark(h(X)), h(ok(X)) -> ok(h(X)), proper(c(X)) -> c(proper(X)), proper(f(X)) -> f(proper(X)), proper(g(X)) -> g(proper(X)), proper(d(X)) -> d(proper(X)), proper(h(X)) -> h(proper(X)), top(mark(X)) -> top(proper(X)), top(ok(X)) -> top(active(X)) } DUP: We consider a non-duplicating system. Trs: { c(ok(X)) -> ok(c(X)), f(mark(X)) -> mark(f(X)), f(ok(X)) -> ok(f(X)), g(ok(X)) -> ok(g(X)), active(c(X)) -> mark(d(X)), active(f(X)) -> f(active(X)), active(f(f(X))) -> mark(c(f(g(f(X))))), active(h(X)) -> mark(c(d(X))), active(h(X)) -> h(active(X)), d(ok(X)) -> ok(d(X)), h(mark(X)) -> mark(h(X)), h(ok(X)) -> ok(h(X)), proper(c(X)) -> c(proper(X)), proper(f(X)) -> f(proper(X)), proper(g(X)) -> g(proper(X)), proper(d(X)) -> d(proper(X)), proper(h(X)) -> h(proper(X)), top(mark(X)) -> top(proper(X)), top(ok(X)) -> top(active(X)) } Matrix Interpretation: Interpretation class: triangular [X1] [1 0][X1] [0] [top]([X0]) = [0 0][X0] + [0] [X1] [1 6][X1] [3] [ok]([X0]) = [0 1][X0] + [7] [X1] [1 1][X1] [0] [proper]([X0]) = [0 1][X0] + [0] [X1] [1 7][X1] [0] [h]([X0]) = [0 1][X0] + [7] [X1] [1 6][X1] [0] [d]([X0]) = [0 1][X0] + [4] [X1] [1 6][X1] [2] [active]([X0]) = [0 1][X0] + [5] [X1] [1 1][X1] [0] [g]([X0]) = [0 1][X0] + [1] [X1] [1 2][X1] [0] [f]([X0]) = [0 1][X0] + [2] [X1] [1 2][X1] [0] [c]([X0]) = [0 1][X0] + [2] [X1] [1 1][X1] [4] [mark]([X0]) = [0 1][X0] + [2] Qed