Excision in bivariant periodic cyclic cohomology: a categorical approach
  We extend Cuntz-Quillen's excision theorem for algebras and pro-algebras in arbitrary Q-linear categories with tensor product.The excision theorems for the bivariant periodic cyclic cohomology of discrete,topological and bornological algebras and pro-algebras follow from this. 
Guillermo Corti\~nas (Univ. of Buenos Aires), Christian Valqui (IMCA   and PUCP of Lima, Per\'u.)