E. Zafiris, GENERALIZED RAYCHAUDHURI AND AREA CHANGE EQUATIONS FOR CLASSICAL BRANE MODELS - ART. NO. 043509, Physical review. D. Particles and fields, 5804(4), 1998, pp. 3509
In this paper we derive the generalizations of Raychaudhuri and area c
hange equations for brane worldsheet congruences embedded in spacetime
s with torsion. The kinematical description we develop is fully covari
ant and based on the use of projection tensors. We apply our results t
o the case of string models.