3 papers
gr-qc2026
Photon surfaces extension in general spherical dust collapse
Roberto Giambò, Camilla Lucamarini
We extend the analysis of photon surfaces in spherical dust collapse to the general, non-marginally bound case, i.e.\ allowing the \textit{energy function} of the Lema\^ıtre…
math.DS2015
On the normal exponential map in singular conformal metrics
R. Giambò, F. Giannoni, P. Piccione
Brake orbits and homoclinics of autonomous dynamical systems correspond, via Maupertuis principle, to geodesics in Riemannian manifolds endowed with a metric which is singular on t…
math.DS2004
Orthogonal Geodesic Chords, Brake Orbits and Homoclinic Orbits in Riemannian Manifolds
Roberto Giambó, Fabio Giannoni, Paolo Piccione
The study of solutions with fixed energy of certain classes of Lagrangian (or Hamiltonian) systems is reduced, via the classical Maupertuis--Jacobi variational principle, to the st…