2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/74493We introduce here a method which uses etale neighborhoods to extend results from smooth semi-local rings to arbitrary semi-local rings A by passing to the henselization of a smooth presentation of A. The technique is used to show that etale cohomology of A agrees with Galois cohomology, the Merkuriev-Suslin theorem holds for A, and to describe torsion in K_2(A).Algebraic Geometry14F20 (Primary) 14F22 (Secondary)text