1. CJM 2009 (vol 62 pp. 721)
 Boocher, Adam; Daub, Michael; Johnson, Ryan K.; Lindo, H.; Loepp, S.; Woodard, Paul A.

Formal Fibers of Unique Factorization Domains
Let $(T,M)$ be a complete local (Noetherian) ring such that $\dim T\geq 2$ and
$T=T/M$ and let $\{p_i\} _{i \in \mathcal I}$ be a collection of
elements of T indexed by a set $\mathcal I$ so that $\mathcal I  < T$.
For each $i \in \mathcal{I}$, let $C_i$:={$Q_{i1}$,$\dots$,$Q_{in_i}$}
be a set of nonmaximal prime ideals containing $p_i$ such that the $Q_{ij}$
are incomparable and $p_i\in Q_{jk}$ if and only if $i=j$. We provide necessary
and sufficient conditions so that T is the ${\bf m}$adic completion of a local unique
factorization domain $(A, {\bf m})$, and for each $i \in \mathcal I$, there exists a unit
$t_i$ of T so that $p_{i}t_i \in A$ and $C_i$
is the set of prime ideals $Q$ of $T$ that are maximal with respect to the condition
that $Q \cap A = p_{i}t_{i}A$.
We then use this result to construct a
(nonexcellent) unique factorization domain containing many ideals for which tight closure and
completion do not commute. As another application, we construct a unique factorization
domain A most of whose formal fibers are geometrically regular.
Categories:13J10, 13J05 
