Jeremy HaefnerEprints
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The Isomorphism problem for incidence rings
(University of California, 1999)Let P and P’ be finite preordered sets, and let R be a ring for which the number of nonzero summands in a direct decomposition of the regular module RR is bounded. We show that if the incidence rings I(P;R) and I(P’;R) ... 
Strongly graded hereditary orders
(20010828)Let R be a Dedekind domain with global quotient field K. The purpose of this note is to provide a characterization of when a strongly graded Rorder with semiprime 1component is hereditary. This generalizes earlier work ... 
Automorphisms of tiled orders
(Elsevier, 2002)Let Λ be a tiled Rorder. We give a description of AutR(Λ) as the semidirect product of Inn(Λ) and a certain subgroup of Aut(Q(Λ)), where Q(Λ) is the link graph of Λ. Additionally, we give criteria for determining when ... 
The Globalization problem for inner automorphisms and SkolemNoether theorems
(World Science, 200307)We investigate the circumstances under which an inner automorphism of a ring with local units can be built from “local” information. Specifically, we consider three natural “inner” type properties for an automorphism of ... 
Hereditary crossed products
(American Mathmatical Society, 20000327)We characterize when a crossed product order over a maximal order in a central simple algebra by a finite group is hereditary. We need only concentrate on the cases when the group acts as inner automorphisms and when ... 
On when a graded ring is graded equivalent to a crossed product
(American Mathmatical Society, 199604)Let R be a ring graded by a group G. We are concerned with describing those Ggraded rings that are graded equivalent to Gcrossed products. We give necessary and sufficient conditions for when a strongly graded ring ... 
Isomorphisms of row and column finite matrix rings
(American Mathmatical Society, 199706)This paper investigates the ringtheoretic similarities and the cate gorical dissimilarities between the ring RFM(R) of row finite matrices and the ring RCFM(R) of row and column finite matrices. For example, we prove ... 
Graded equivalence theory with applications
(Elsevier, 19950301)We develop the foundations for graded equivalence theory and apply them to investigate properties such as primeness, finite representation type, and vertex theory of graded rings. The key fact that we prove is that, for ... 
Mind over matter: Transforming course management systems into effective learning environments
(EDUCAUSE, 200212)Integrating best practices for "deeper learning" with the robust tools provided by course management systems creates an incredibly effective, engaging, and studentcentered learning environment. 
Local orders whose lattices are direct sums of ideals
(American Mathematical Society, 199010)Let R be a complete local Dedekind domain with quotient field K and let A be a local Rorder in a separable Kalgebra. This paper classifies those orders A such that every indecomposable Rtorsionfree Amodule is isomorphic ... 
Approximating rings with local units via automorphisms
(Springer Verlag, 199902)For a ring A with local units we investigate unital overrings T of A, and compare the automorphism groups Aut(A) and Aut(T ).