Convergence to equilibria in the Lorenz system via monotone methods

In this paper, we provide some parameter values of the Lorenz system for which its flow is monotone with respect to the order induced by quadratic cones. This implies that its attractor is contained in a two-dimensional invariant manifold. An application of Dulac's criterion to the induced flow over that manifold leads to conditions under which every positive semiorbit converges to an equilibrium.