The Behavior on the Restriction of Divisor Classes to Sequences of Hypersurfaces

40 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2003.Let A be an excellent local normal domain and fninfinity n=1 a sequence of prime elements lying in successively higher powers of the maximal ideal, such that each hypersurface A/ fnA satisfies R1. We establish the map of divisor classes jn*: Cl(A) → Cl((A/fnA)'), where (A/fnA)' represents the integral closure, and investigate the injectivity of jn*. The first result shows that no nontrivial divisor class can lie in every kernel. Secondly, when A is an isolated singularity containing a field of characteristic zero, dim A ≥ 4, and A has a small Cohen-Macaulay module, then we show that there is an integer N > 0 such that fn ∈ mN ⇒ jn* is injective. We substantiate these results with a general construction that provides a large collection of examples.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD