New Products, Chern Classes, and Power Operations in Orbifold K-theory
  Withdrawn by the authors because the results of this paper are subsumed within and improved by the two papers   1. A plethora of inertial products and   2. Chern Classes and Compatible Power Operations in Inertial K-theory 
Dan Edidin, Tyler J. Jarvis, Takashi Kimura
math.AG hep-th math.KT