3 papers
gr-qc2003
Projective connections associated with second order ODEs
Ezra T Newman, Pawel Nurowski
We show that every 2nd order ODE defines a 4-parameter family of projective connections on its 2-dimensional solution space. In a special case of ODEs, for which a certain point tr…
gr-qc2000
Singularities of wavefronts and lightcones in the context of GR via null foliations
Simonetta Frittelli, Ezra T. Newman
We describe an approach to the issue of the singularities of null hypersurfaces, due to the focusing of null geodesics, in the context of the recently introduced formulation of GR…
gr-qc1998
A variational principle for time of arrival of null geodesics
Simonetta Frittelli, Ezra T. Newman
Normally the issue or question of the time of arrival of light rays at an observer coming from a given source is associated with Fermat's Principle of Least Time which yields paths…