3 citations · 3 across the 8 of their papers we have counts for
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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…
Spectral stability, spectral flow and circular relative equilibria for the Newtonian -body problem
Luca Asselle, Alessandro Portaluri, Li Wu
For the Newtonian (gravitational) -body problem in the Euclidean -dimensional space, , the simplest possible periodic solutions are provided by circular relative equi…
Mean index for non-periodic orbits in Hamiltonian systems
Xijun Hu, Li Wu
In this paper, we define mean index for non-periodic orbits in Hamiltonian systems and study its properties. In general, the mean index is an interval in R which is uniformly conti…
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…
Multiplicity of closed characteristics on -symmetric compact convex hypersurfaces in
Lei Liu, Li Wu
There is a long standing conjecture that there are at least closed characteristics for any compact convex hypersurface in , and the symmetric case, i.e. $Σ…