Carl Faith

Injective Modules and Injective Quotient Rings, in two parts, is the only book of its kind to combine commutative and noncommutative ring theory. This unique and outstanding contribution to the mathematical literature will immediately advance the studies of mathematicians and graduate students in the field.Written by a leading expert in the field, Injective Modules and Injective Quotient Rings offers readers the key concepts and methods used in both noncommutative and commutative ring theory. Part I provides the first non-torsion-theory proof of the Teply-Miller theorem and the first statement and proof of the converse of the Teply-Miller-Hansen theorem. Many applications of these theorems to the structure of rings and modules are given, including generalizations of theorems of Cailleau-Beck and Matlis on the structure of ?-injectives and commutative rings. Part II provides an alternative approach to the solution of Kaplansky's problem on the classification of FGC rings. Of particular importance is the consistent use of noncommutative ring theoretical techniques throughout Part II to obtain theorems lying purely in the domain of commutative ring theory.Graduate students and mathematicians in both commutative and noncommutative ring theory will learn from the unique approach and new general methods in ring theory contained in Injective Modules and Injective Quotient Rings.

VI of Oregon lectures in 1962, Bass gave simplified proofs of a number of "Morita Theorems", incorporating ideas of Chase and Schanuel. One of the Morita theorems characterizes when there is an equivalence of categories mod-A R::! mod-B for two rings A and B. Morita's solution organizes ideas so efficiently that the classical Wedderburn-Artin theorem is a simple consequence, and moreover, a similarity class [AJ in the Brauer group Br(k) of Azumaya algebras over a commutative ring k consists of all algebras B such that the corresponding categories mod-A and mod-B consisting of k-linear morphisms are equivalent by a k-linear functor. (For fields, Br(k) consists of similarity classes of simple central algebras, and for arbitrary commutative k, this is subsumed under the Azumaya [51]1 and Auslander-Goldman [60J Brauer group. ) Numerous other instances of a wedding of ring theory and category (albeit a shot­ gun wedding!) are contained in the text. Furthermore, in. my attempt to further simplify proofs, notably to eliminate the need for tensor products in Bass's exposition, I uncovered a vein of ideas and new theorems lying wholely within ring theory. This constitutes much of Chapter 4 -the Morita theorem is Theorem 4. 29-and the basis for it is a corre­ spondence theorem for projective modules (Theorem 4. 7) suggested by the Morita context. As a by-product, this provides foundation for a rather complete theory of simple Noetherian rings-but more about this in the introduction.

This work specifically surveys simple Noetherian rings. The authors present theorems on the structure of simple right Noetherian rings and, more generally, on simple rings containing a uniform right ideal U. The text is as elementary and self-contained as practicable, and the little background required in homological and categorical algebra is given in a short appendix. Full definitions are given and short, complete, elementary proofs are provided for such key theorems as the Morita theorem, the Correspondence theorem, the Wedderburn–Artin theorem, the Goldie–Lesieur–Croisot theorem, and many others. Complex mathematical machinery has been eliminated wherever possible or its introduction into the text delayed as long as possible. (Even tensor products are not required until Chapter 3.)

This work includes all known theorems on the subject of noncommutative FPF rings.

First published in 1982. These lectures are in two parts. Part I, entitled injective Modules Over Levitzki Rings, studies an injective module E and chain conditions on the set A^(E,R) of right ideals annihilated by subsets of E. Part II is on the subject of (F)PF, or (finitely) pseudo-Frobenius, rings [i.e., all (finitely generated) faithful modules generate the category mod-R of all R-modules]. (The PF rings had been introduced by Azumaya as a generalization of quasi-Frobenius rings, but FPF includes infinite products of Prufer domains, e.g., Z w .)