This text, drawn from the author's lectures at the University of California at Berkeley, is intended as a textbook for a one-term course in basic ring theory. The material covered includes the Wedderburn-Artin theory of semi-simple rings, Jacobson's theory of the radical representation theory of groups and algebras, prime and semi-prime rings, primitive and semi-primitive rings, division rings, ordered rings, local and semi-local rings, and perfect and semi-perfect rings. By aiming the level of writing at the novice rather than at the expert, and by stressing the role of examples and motivation, the author has produced a text which is suitable not only for use in a graduate course, but also for self-study by other interested graduate students. Numerous exercises are also included. This graduate textbook on rings, fields and algebras is intended for graduate students in mathematics.

A first course in noncommutative rings, by T. Y. Lam. Pp. 385. £37 (pb), £62.50 (hb). 2001. ISBN 0 387 95325 6 (pb), 0 387 95183 0 (hb) (Springer-Verlag).

This paper introduces five notions, including π-algebras, π-ideals, Hopf π-algebras, π-modules and Hopf π-modules, verifies the fundamental isomorphism theorem of π-algebras and studies some algebraic properties of Hopf π-algebras as well.

Hopf π- Algebras

This volume provides a comprehensive introduction to module theory and the related part of ring theory, including original results as well as the most recent work. It is a useful and stimulating study for those new to the subject as well as for researchers and serves as a reference volume. Starting form a basic understanding of linear algebra, the theory is presented and accompanied by complete proofs. For a module M, the smallest Grothendieck category containing it is denoted by o[M] and module theory is developed in this category. Developing the techniques in o[M] is no more complicated than in full module categories and the higher generality yields significant advantages: for example, module theory may be developed for rings without units and also for non-associative rings. Numerous exercises are included in this volume to give further insight into the topics covered and to draw attention to related results in the literature.

Foundations of Module and Ring Theory : A Handbook for Study and Research

The Algebraic Theory of Semigroups, Vol. I. By A. H. Clifford and G. B. Preston. Pp. xv + 224. $10.60. 1961. (American Mathematical Society, Providence.)

This ACM volume deals with tackling problems that can be represented by data structures which are essentially matrices with polynomial entries, mediated by the disciplines of commutative algebra and algebraic geometry. The discoveries stem from an interdisciplinary branch of research which has been growing steadily over the past decade. The author covers a wide range, from showing how to obtain deep heuristics in a computation of a ring, a module or a morphism, to developing means of solving nonlinear systems of equations - highlighting the use of advanced techniques to bring down the cost of computation. Although intended for advanced students and researchers with interests both in algebra and computation, many parts may be read by anyone with a basic abstract algebra course.

Computational methods in commutative algebra and algebraic geometry

On monomial algebras

Several aspects of relations between braces and non-degenerate involutive set-theoretic solutions of the Yang–Baxter equation are discussed and many consequences are derived In particular, for each positive integer n a finite square-free multipermutation solution of the Yang–Baxter equation with multipermutation level n and an abelian involutive Yang–Baxter group is constructed This answers a problem of Gateva-Ivanova and Cameron It is proved that finite non-degenerate involutive set-theoretic solutions of the Yang–Baxter equation whose associated involutive Yang–Baxter group is abelian are multipermutation solutions Earlier the authors proved this with the additional square-free hypothesis on the solutions It is also proved that finite square-free non-degenerate involutive set-theoretic solutions associated to a left brace are multipermutation solutions

Braces and the Yang-Baxter Equation

Several aspects of relations between braces and non-degenerate involutive set-theoretic solutions of the Yang-Baxter equation are discussed and many consequences are derived. In particular, for each positive integer $n$ a finite square-free multipermutation solution of the Yang-Baxter equation with multipermutation level $n$ and an abelian involutive Yang-Baxter group is constructed. This answers a problem of Gateva-Ivanova and Cameron. It is also proved that finite non-degenerate involutive set-theoretic solutions of the Yang-Baxter equation whose associated involutive Yang-Baxter group is abelian are retractable in the sense of Etingof, Schedler and Soloviev. Earlier the authors proved this with the additional square-free hypothesis on the solutions. Retractability of solutions is also proved for finite square-free non-degenerate involutive set-theoretic solutions associated to a left brace.

Braces and the Yang-Baxter equation

1. Introduction. 2. Prerequisites on semigroup theory. 2.1 Semigroups. 2.2. Uniform semigroups. 2.3 Full linear semigroup. 2.4 Structure of linear semigroups. 2.5 Closure. 2.6 Semigroups over a field. 3. Prerequisites on ring theory. 3.1 Noetherian rings and rings satisfying a polynomial identity. 3.2 Prime ideals. 3.3 Group algebras of polycyclic-by-finite groups. 3.4 Graded rings. 3.5 Gelfand-Kirillov dimension. 3.6 Maximal orders. 3.7 Principal ideal rings. 4. Algebras of submonoids of polycylic-by-finite groups. 4.1 Ascending chain condition. 4.2 The unit group. 4.3 Almost nilpotent case. 4.4 Structure theorem. 4.5 Prime ideals of K[S]. 4.6 Comments and problems. 5. General Noetherian semigroup algebras. 5.1 Finite generation of the monoid. 5.2 Necessary conditions. 5.3 Monomial semigroups and sufficient conditions. 5.4 Gelfand-Kirillov dimension. 5.5 Comments and problems. 6. Principal ideal rings. 6.1 Group algebras. 6.2 Matrix embedding. 6.3 Finite dimensional case. 6.4 The general case. 6.5 Comments and problems. 7. Maximal orders and Noetherian semigroup algebras. 7.1 Maximal orders and monoids. 7.2 Algebras of submonoids of abelian-by-finite groups. 7.3 Comments and problems. 8. Monoids of I-type. 8.1 A characterization. 8.2 Structure of monoids of I-type. 8.3 Binomial monoids are of I-type. 8.4 Decomposable monoids of I-type. 8.5 Algebras of monoids of I-type. 8.6 Comments and problems. 9. Monoids of skew type. 9.1 Definition. 9.2 Monoids of skew type and the cyclic condition. 9.3 Non-degenerate monoids of skew type. 9.4 Algebras of non-degenerate monoids of skew type. 9.5 The cancellative congruence and the prime radical. 9.6 Comments and problems. 10. Examples. 10.1 Monoids of skew type and the Gelfand-Kirillov dimension. 10.2 Four generated monoids of skew type. 10.3 Examples of Gelfand-Kirillov dimension 2. 10.4 Non-degenerate monoids of skew type of Gelfand-Kirillov dimension one. 10.5 Examples of maximal orders. 10.6 Comments. Bibliography. Index. Notation.

Jan Okniński

Papers

On monomial algebras

Braces and the Yang-Baxter Equation

Braces and the Yang-Baxter equation

Noetherian Semigroup Algebras

Retractability of set theoretic solutions of the Yang-Baxter equation