Given a functor T:C -> D carrying a class of morphisms S in C into a class
S' in D, we give sufficient conditions in order that T induces an
equivalence on the localised categories. These conditions are in the
spirit of Quillen's theorem A. We give some applications in algebaic and
birational geometry.
This is an update of preprint #804, and has appeared as Homology, Homotopy and
Applications, Vol. 9 (2007), No. 2, pp.137-161. See http://www.intlpress.com/HHA/v9/n2/a5/.