Nonholonomic lorentzian geometry on some H-type groups

Abstract

We consider examples of H-type Carnot groups whose noncommutative multiplication law gives rise to a smooth 2-step bracket generating distribution of the tangent bundle. In the contrast with the previous studies we furnish the horizontal distribution with the Lorentzian metric, which is nondegenerate metric of index 1, instead of a positive definite quadratic form. The causal character is defined. We study the reachable set by timelike future directed curves. The parametric equations of geodesics are obtained. © Mathematica Josephina, Inc. 2009.