7 citations · 12 across the 9 of their papers we have counts for
9 papers
Morse index of circular solutions for attractive central force problems on surfaces
Stefano Baranzini, Alessandro Portaluri, Ran Yang
The classical theory of attractive central force problem on the standard (flat) Euclidean plane can be generalized to surfaces by reformulating the basic underlying physical princi…
Energy stability and convergence of variable-step L1 scheme for the time fractional Swift-Hohenberg model
Xuan Zhao, Ran Yang, Ren-jun Qi +1
A fully implicit numerical scheme is established for solving the time fractional Swift-Hohenberg (TFSH) equation with a Caputo time derivative of order . The variable-st…
Energy stable and norm convergent BDF3 scheme for the Swift-Hohenberg equation
Xuan Zhao, Ran Yang, Zhongqin Xue +1
A fully discrete implicit scheme is proposed for the Swift-Hohenberg model, combining the third-order backward differentiation formula (BDF3) for the time discretization and the se…
A generalized index theory for non-Hamiltonian system
Alessandro Portaluri, Li Wu, Ran Yang
Morse index theory provides an elegant and useful tool for describing several aspects of a Lagrangian system in terms of its variational properties. In the classical framework it p…
Linear instability of periodic orbits of free period Lagrangian systems
Alessandro Portaluri, Li Wu, Ran Yang
In this paper we provide a sufficient condition for the linear instability of a periodic orbit for a free period Lagrangian system on a Riemannian manifold. The main result establi…
Linear instability for periodic orbits of non-autonomous Lagrangian systems
Alessandro Portaluri, Li Wu, Ran Yang
Inspired by the classical Poincaré criterion about the instability of orientation preserving minimizing closed geodesics on surfaces, we investigate the relation intertwining the i…
Morse Index Theorem of Lagrangian Systems and Stability of Brake Orbit
Xijun Hu, Li Wu, Ran Yang
In this paper, we prove Morse index theorem of Lagrangian system with any self-adjoint boundary conditions. Based on it, we give some nontrivial estimation on the difference of Mor…
Instability of semi-Riemannian closed geodesics
Xijun Hu, Alessandro Portaluri, Ran Yang
A celebrated result due to Poincaré affirms that a closed non-degenerate minimizing geodesic on an oriented Riemannian surface is hyperbolic. Starting from this classical theor…
A dihedral Bott-type iteration formula and stability of symmetric periodic orbits
Xijun Hu, Alessandro Portaluri, Ran Yang
In 1956, Bott in his celebrated paper on closed geodesics and Sturm intersection theory, proved an Index Iteration Formula for closed geodesics on Riemannian manifolds. Some years…