Computational Geometry of Positive Definite Quadratic Forms

Computational Geometry of Positive Definite Quadratic Forms PDF

Author: Achill Schurmann

Publisher: American Mathematical Soc.

Published: 2009

Total Pages: 183

ISBN-13: 082184735X

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"Starting from classical arithmetical questions on quadratic forms, this book takes the reader step by step through the connections with lattice sphere packing and covering problems. As a model for polyhedral reduction theories of positive definite quadratic forms, Minkowski's classical theory is presented, including an application to multidimensional continued fraction expansions. The reduction theories of Voronoi are described in great detail, including full proofs, new views, and generalizations that cannot be found elsewhere. Based on Voronoi's second reduction theory, the local analysis of sphere coverings and several of its applications are presented. These include the classification of totally real thin number fields, connections to the Minkowski conjecture, and the discovery of new, sometimes surprising, properties of exceptional structures such as the Leech lattice or the root lattices." "Throughout this book, special attention is paid to algorithms and computability, allowing computer-assisted treatments. Although dealing with relatively classical topics that have been worked on extensively by numerous authors, this book is exemplary in showing how computers may help to gain new insights."--BOOK JACKET.

Quadratic Forms -- Algebra, Arithmetic, and Geometry

Quadratic Forms -- Algebra, Arithmetic, and Geometry PDF

Author: Ricardo Baeza

Publisher: American Mathematical Soc.

Published: 2009-08-14

Total Pages: 424

ISBN-13: 0821846485

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This volume presents a collection of articles that are based on talks delivered at the International Conference on the Algebraic and Arithmetic Theory of Quadratic Forms held in Frutillar, Chile in December 2007. The theory of quadratic forms is closely connected with a broad spectrum of areas in algebra and number theory. The articles in this volume deal mainly with questions from the algebraic, geometric, arithmetic, and analytic theory of quadratic forms, and related questions in algebraic group theory and algebraic geometry.

The Algebraic and Geometric Theory of Quadratic Forms

The Algebraic and Geometric Theory of Quadratic Forms PDF

Author: Richard S. Elman

Publisher: American Mathematical Soc.

Published: 2008-07-15

Total Pages: 456

ISBN-13: 9780821873229

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This book is a comprehensive study of the algebraic theory of quadratic forms, from classical theory to recent developments, including results and proofs that have never been published. The book is written from the viewpoint of algebraic geometry and includes the theory of quadratic forms over fields of characteristic two, with proofs that are characteristic independent whenever possible. For some results both classical and geometric proofs are given. Part I includes classical algebraic theory of quadratic and bilinear forms and answers many questions that have been raised in the early stages of the development of the theory. Assuming only a basic course in algebraic geometry, Part II presents the necessary additional topics from algebraic geometry including the theory of Chow groups, Chow motives, and Steenrod operations. These topics are used in Part III to develop a modern geometric theory of quadratic forms.

The Sensual (Quadratic) Form

The Sensual (Quadratic) Form PDF

Author: John Horton Conway

Publisher: Cambridge University Press

Published: 1997

Total Pages: 180

ISBN-13: 9780883850305

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Quadratic forms are presented in a pictorial way, elucidating many topics in algebra, number theory and geometry.

Quadratic Forms and Their Applications

Quadratic Forms and Their Applications PDF

Author: Eva Bayer-Fluckiger

Publisher: American Mathematical Soc.

Published: 2000

Total Pages: 330

ISBN-13: 0821827790

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This volume outlines the proceedings of the conference on "Quadratic Forms and Their Applications" held at University College Dublin. It includes survey articles and research papers ranging from applications in topology and geometry to the algebraic theory of quadratic forms and its history. Various aspects of the use of quadratic forms in algebra, analysis, topology, geometry, and number theory are addressed. Special features include the first published proof of the Conway-Schneeberger Fifteen Theorem on integer-valued quadratic forms and the first English-language biography of Ernst Witt, founder of the theory of quadratic forms.

Geometric Methods in the Algebraic Theory of Quadratic Forms

Geometric Methods in the Algebraic Theory of Quadratic Forms PDF

Author: Oleg T. Izhboldin

Publisher: Springer

Published: 2004-02-07

Total Pages: 198

ISBN-13: 3540409904

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The geometric approach to the algebraic theory of quadratic forms is the study of projective quadrics over arbitrary fields. Function fields of quadrics have been central to the proofs of fundamental results since the 1960's. Recently, more refined geometric tools have been brought to bear on this topic, such as Chow groups and motives, and have produced remarkable advances on a number of outstanding problems. Several aspects of these new methods are addressed in this volume, which includes an introduction to motives of quadrics by A. Vishik, with various applications, notably to the splitting patterns of quadratic forms, papers by O. Izhboldin and N. Karpenko on Chow groups of quadrics and their stable birational equivalence, with application to the construction of fields with u-invariant 9, and a contribution in French by B. Kahn which lays out a general framework for the computation of the unramified cohomology groups of quadrics and other cellular varieties.

Bilinear Algebra

Bilinear Algebra PDF

Author: Kazimierz Szymiczek

Publisher: Routledge

Published: 2017-11-22

Total Pages: 496

ISBN-13: 1351464213

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Giving an easily accessible elementary introduction to the algebraic theory of quadratic forms, this book covers both Witt's theory and Pfister's theory of quadratic forms. Leading topics include the geometry of bilinear spaces, classification of bilinear spaces up to isometry depending on the ground field, formally real fields, Pfister forms, the Witt ring of an arbitrary field (characteristic two included), prime ideals of the Witt ring, Brauer group of a field, Hasse and Witt invariants of quadratic forms, and equivalence of fields with respect to quadratic forms. Problem sections are included at the end of each chapter. There are two appendices: the first gives a treatment of Hasse and Witt invariants in the language of Steinberg symbols, and the second contains some more advanced problems in 10 groups, including the u-invariant, reduced and stable Witt rings, and Witt equivalence of fields.