%0 Journal Article
%T Transverse Riemann-Lorentz metrics with tangent radical
%A E. Aguirre-Daban
%A J. Lafuente-Lopez
%J Mathematics
%D 2003
%I arXiv
%X Consider a smooth manifold with a smooth metric which changes bilinear type from Riemann to Lorentz on a hypersurface $\Sigma$ with radical tangent to $\Sigma$. Two natural bilinear symmetric forms appear there, and we use it to analyze the geometry of $\Sigma$. We show the way in which these forms control the smooth extensibility over $\Sigma$ of the covariant, sectional and Ricci curvatures of the Levi-Civita connection outside $\Sigma$.
%U http://arxiv.org/abs/math/0306153v1