Removal and Contraction Operations in $n$D Generalized Maps for   Efficient Homology Computation
  In this paper, we show that contraction operations preserve the homology of $n$D generalized maps, under some conditions. Removal and contraction operations are used to propose an efficient algorithm that compute homology generators of $n$D generalized maps. Its principle consists in simplifying a generalized map as much as possible by using removal and contraction operations. We obtain a generalized map having the same homology than the initial one, while the number of cells decreased significantly.   Keywords: $n$D Generalized Maps; Cellular Homology; Homology Generators; Contraction and Removal Operations. 
Guillaume Damiand, Rocio Gonzalez-Diaz, Samuel Peltier
cs.CV