A recurring theme in a traditional introductory graduate algebra course is the existence and consequences of relationships between different algebraic structures. This is also the theme of this book, an exposition of connections between representations of finite partially ordered sets and abelian groups. Emphasis is placed throughout on classification, a description of the objects up to isomorphism, and computation of representation type, a measure of when classification is feasible. David M. Arnold is the Ralph and Jean Storm Professor of Mathematics at Baylor University. He is the author of "Finite Rank Torsion Free Abelian Groups and Rings" published in the Springer-Verlag Lecture Notes in Mathematics series, a co-editor for two volumes of conference proceedings, and the author of numerous articles in mathematical research journals. His research interests are in abelian group theory and related topics, such as representations of partially ordered sets and modules over discrete valuation rings, subrings of algebraic number fields, and pullback rings. He received his Ph. D. from the University of Illinois, Urbana and was a member of the faculty at New Mexico State University for many years.

Inhalt
1 Representations of Posets over a Field.- 1.1 Vector Spaces with Distinguished Subspaces.- 1.2 Representations of Posets and Matrix Problems.- 1.3 Finite Representation Type.- 1.4 Tame and Wild Representation Type.- 1.5 Generic Representations.- 2 Torsion-Free Abelian Groups.- 2.1 Quasi-isomorphism and Isomorphism at p.- 2.2 Near-isomorphism of Finite Rank Groups.- 2.3 Stable Range Conditions for Finite Rank Groups.- 2.4 Self-Small Groups and Endomorphism Rings.- 3 Butler Groups.- 3.1 Types and Completely Decomposable Groups.- 3.2 Characterizations of Finite Rank Groups.- 3.3 Quasi-isomorphism and ?-Representations of Posets.- 3.4 Countable Groups.- 3.5 Quasi-Generic Groups.- 4 Representations over a Discrete Valuation Ring.- 4.1 Finite and Rank-Finite Representation Type.- 4.2 Wild Modulo p Representation Type.- 4.3 Finite Rank Butler Groups and Isomorphism at p.- 5 Almost Completely Decomposable Groups.- 5.1 Characterizations and Properties.- 5.2 Isomorphism at p and Representation Type.- 5.3 Uniform Groups.- 5.4 Primary Regulating Quotient Groups.- 6 Representations over Fields and Exact Sequences.- 6.1 Projectives, Injectives, and Exact Sequences.- 6.2 Coxeter Correspondences.- 6.3 Almost Split Sequences.- 6.4 A Torsion Theory and Localizations.- 7 Finite Rank Butler Groups.- 7.1 Projectives, Injectives, and Exact Sequences.- 7.2 Endomorphism Rings.- 7.3 Bracket Groups.- 8 Applications of Representations and Butler Groups.- 8.1 Torsion-Free Modules over Discrete Valuation Rings.- 8.2 Finite Valuated Groups.- References.- List of Symbols.- Index of Terms.