Myron Mathisson: What little we know of his life

Myron Mathisson (1897–1940) was a Polish Jew known for his work on the equations of motion of bodies in general relativity and for developing a new method to analyze the properties of fundamental solutions of linear hyperbolic differential equations. In particular, he derived the equations for a spinning body moving in a gravitational field and proved, in a special case, the Hadamard conjecture on the class of equations that satisfy the Huygens principle. His work still exerts influence on current research. Drawing on various archival and secondary sources, in particular his correspondence with Einstein, we outline Mathisson’s biography and scientific career

Robinson Manifolds as the Lorentzian Analogs of Hermite Manifolds

A Lorentzian manifold is defined here as a smooth pseudo-Riemannian manifold with a metric tensor of signature ((2n +1, 1)). A Robinson manifold is a Lorentzian manifold (M) of dimension (\geqslant 4) with a subbundle (N) of the complexification of (TM) such that the fibers of (N\to M) are maximal totally null (isotropic) and ([\Sec N, \Sec N]\subset \Sec N). Robinson manifolds are close analogs of the proper Riemannian, Hermite manifolds. In dimension 4, they correspond to space-times of general relativity, foliated by a family of null geodesics without shear. Such space-times, introduced in the 1950s by Ivor Robinson, played an important role in the study of solutions of Einstein's equations: plane and sphere-fronted waves, the G\"odel universe, the Kerr solution, and their generalizations, are among them. In this survey article, the analogies between Hermite and Robinson manifolds are presented in considerable detail

A criterion for compatibility of conformal and projective structures

In a space-time, a conformal structure is defined by the distribution of light-cones. Geodesics are traced by freely falling particles, and the collection of all unparameterized geodesics determines the projective structure of the space-time. The article contains a formulation of the necessary and sufficient conditions for these structures to be compatible, i.e. to come from a metric tensor which is then unique up to a constant factor. The theorem applies to all dimensions and signatures.Comment: 5 page