Orbifold String Topology
  In this paper we study the string topology (\'a la Chas-Sullivan) of an orbifold. We define the string homology ring product at the level of the free loop space of the classifying space of an orbifold. We study its properties (introducing an operad to do so) and do some explicit calculations. 
Ernesto Lupercio, Bernardo Uribe, Miguel A. Xicotencatl