The aim of this Note is the study of light rays that join an event p with a timelike curve gamma in a light-convex open subset Lambda of a stably causal Lorentzian manifold M. We present an intrinsic approach to the Theory of Ljusternik and Schnirelman and to the Morse Theory in the space of H-1,H-2-lightlike curves joining p and gamma. The theory may give a mathematical model for the so called gravitational lensing effect in astrophysics.

A variational theory for hight rays on Lorentz manifolds / Giannoni, F; Masiello, A; Piccione, P. - In: COMPTES RENDUS DE L'ACADÉMIE DES SCIENCES. SÉRIE 1, MATHÉMATIQUE. - ISSN 0764-4442. - STAMPA. - 324:10(1997), pp. 1093-1097. [10.1016/S0764-4442(97)87893-7]

A variational theory for hight rays on Lorentz manifolds

Masiello, A;