Extended Affine Lie Algebras and Their Root Systems

Extended Affine Lie Algebras and Their Root Systems PDF Author: Bruce Normansell Allison
Publisher: American Mathematical Soc.
ISBN: 0821805940
Category : Mathematics
Languages : en
Pages : 138

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Book Description
This work is about extended affine Lie algebras (EALA's) and their root systems. EALA's were introduced by Høegh-Krohn and Torresani under the name irreducible quasi-simple Lie algebras. The major objective is to develop enough theory to provide a firm foundation for further study of EALA's. The first chapter of the paper is devoted to establishing some basic structure theory. It includes a proof of the fact that, as conjectured by Kac, the invariant symmetric bilinear form on an EALA can be scaled so that its restriction to the real span of the root system is positive semi-definite. The second chapter studies extended affine root systems (EARS) which are an axiomatized version of the root systems arising from EALA's. The concept of a semilattice is used to give a complete description of EARS. In the final chapter, a number of new examples of extended affine Lie algebras are given. The concluding appendix contains an axiomatic characterization of the nonisotropic roots in an EARS in a more general context than the one used in the rest of the paper.

Extended Affine Lie Algebras and Their Root Systems

Extended Affine Lie Algebras and Their Root Systems PDF Author: Bruce Normansell Allison
Publisher: American Mathematical Soc.
ISBN: 0821805940
Category : Mathematics
Languages : en
Pages : 138

Get Book

Book Description
This work is about extended affine Lie algebras (EALA's) and their root systems. EALA's were introduced by Høegh-Krohn and Torresani under the name irreducible quasi-simple Lie algebras. The major objective is to develop enough theory to provide a firm foundation for further study of EALA's. The first chapter of the paper is devoted to establishing some basic structure theory. It includes a proof of the fact that, as conjectured by Kac, the invariant symmetric bilinear form on an EALA can be scaled so that its restriction to the real span of the root system is positive semi-definite. The second chapter studies extended affine root systems (EARS) which are an axiomatized version of the root systems arising from EALA's. The concept of a semilattice is used to give a complete description of EARS. In the final chapter, a number of new examples of extended affine Lie algebras are given. The concluding appendix contains an axiomatic characterization of the nonisotropic roots in an EARS in a more general context than the one used in the rest of the paper.

Geometric Representation Theory and Extended Affine Lie Algebras

Geometric Representation Theory and Extended Affine Lie Algebras PDF Author: Erhard Neher
Publisher: American Mathematical Soc.
ISBN: 082185237X
Category : Nonassociative rings
Languages : en
Pages : 226

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Book Description
Lie theory has connections to many other disciplines such as geometry, number theory, mathematical physics, and algebraic combinatorics. The interaction between algebra, geometry and combinatorics has proven to be extremely powerful in shedding new light on each of these areas. This book presents the lectures given at the Fields Institute Summer School on Geometric Representation Theory and Extended Affine Lie Algebras held at the University of Ottawa in 2009. It provides a systematic account by experts of some of the exciting developments in Lie algebras and representation theory in the last two decades. It includes topics such as geometric realizations of irreducible representations in three different approaches, combinatorics and geometry of canonical and crystal bases, finite $W$-algebras arising as the quantization of the transversal slice to a nilpotent orbit, structure theory of extended affine Lie algebras, and representation theory of affine Lie algebras at level zero. This book will be of interest to mathematicians working in Lie algebras and to graduate students interested in learning the basic ideas of some very active research directions. The extensive references in the book will be helpful to guide non-experts to the original sources.

Quantum Affine Algebras, Extended Affine Lie Algebras, and Their Applications

Quantum Affine Algebras, Extended Affine Lie Algebras, and Their Applications PDF Author: Yun Gao, Naihuan Jing, Michael Lau, and Kailash C. Misra
Publisher: American Mathematical Soc.
ISBN: 0821858327
Category : Geometry, Affine
Languages : en
Pages : 314

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Book Description


Quantum Affine Algebras, Extended Affine Lie Algebras, and Their Applications

Quantum Affine Algebras, Extended Affine Lie Algebras, and Their Applications PDF Author: Yun Gao
Publisher: American Mathematical Soc.
ISBN: 0821845071
Category : Mathematics
Languages : en
Pages : 314

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Book Description
This volume contains the proceedings of the conference on Quantum Affine Algebras, Extended Affine Lie Algebras, and Applications, which was held at the Banff International Research Station, Banff, Canada, from March 2-7, 2008. Many of the papers include new results on different aspects of quantum affine algebras, extended affine Lie algebras, and their applications in other areas of mathematics and physics. Any reader interested in learning about the recent developments in quantum affine algebras and extended affine Lie algebras will benefit from this book.

Lie Algebras Graded by the Root Systems BC$_r$, $r\geq 2$

Lie Algebras Graded by the Root Systems BC$_r$, $r\geq 2$ PDF Author: Bruce Normansell Allison
Publisher: American Mathematical Soc.
ISBN: 0821828118
Category : Mathematics
Languages : en
Pages : 175

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Book Description
Introduction The $\mathfrak{g}$-module decomposition of a $\mathrm{BC}_r$-graded Lie algebra, $r\ge 3$ (excluding type $\mathrm{D}_3)$ Models for $\mathrm{BC}_r$-graded Lie algebras, $r\ge 3$ (excluding type $\mathrm{D}_3)$ The $\mathfrak{g}$-module decomposition of a $\mathrm{BC}_r$-graded Lie algebra with grading subalgebra of type $\mathrm{B}_2$, $\mathrm{C}_2$, $\mathrm{D}_2$, or $\mathrm{D}_3$ Central extensions, derivations and invariant forms Models of $\mathrm{BC}_r$-graded Lie algebras with grading subalgebra of type $\mathrm{B}_2$, $\mathrm{C}_2$, $\mathrm{D}_2$, or $\mathrm{D}_3$ Appendix: Peirce decompositions in structurable algebras References.

Infinite Dimensional Lie Algebras

Infinite Dimensional Lie Algebras PDF Author: Victor G. Kac
Publisher: Springer Science & Business Media
ISBN: 1475713827
Category : Mathematics
Languages : en
Pages : 267

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Book Description


Torsors, Reductive Group Schemes and Extended Affine Lie Algebras

Torsors, Reductive Group Schemes and Extended Affine Lie Algebras PDF Author: Philippe Gille
Publisher: American Mathematical Soc.
ISBN: 0821887742
Category : Mathematics
Languages : en
Pages : 124

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Book Description
The authors give a detailed description of the torsors that correspond to multiloop algebras. These algebras are twisted forms of simple Lie algebras extended over Laurent polynomial rings. They play a crucial role in the construction of Extended Affine Lie Algebras (which are higher nullity analogues of the affine Kac-Moody Lie algebras). The torsor approach that the authors take draws heavily from the theory of reductive group schemes developed by M. Demazure and A. Grothendieck. It also allows the authors to find a bridge between multiloop algebras and the work of F. Bruhat and J. Tits on reductive groups over complete local fields.

Developments and Trends in Infinite-Dimensional Lie Theory

Developments and Trends in Infinite-Dimensional Lie Theory PDF Author: Karl-Hermann Neeb
Publisher: Springer Science & Business Media
ISBN: 0817647414
Category : Mathematics
Languages : en
Pages : 492

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Book Description
This collection of invited expository articles focuses on recent developments and trends in infinite-dimensional Lie theory, which has become one of the core areas of modern mathematics. The book is divided into three parts: infinite-dimensional Lie (super-)algebras, geometry of infinite-dimensional Lie (transformation) groups, and representation theory of infinite-dimensional Lie groups. Contributors: B. Allison, D. Beltiţă, W. Bertram, J. Faulkner, Ph. Gille, H. Glöckner, K.-H. Neeb, E. Neher, I. Penkov, A. Pianzola, D. Pickrell, T.S. Ratiu, N.R. Scheithauer, C. Schweigert, V. Serganova, K. Styrkas, K. Waldorf, and J.A. Wolf.

Locally Finite Root Systems

Locally Finite Root Systems PDF Author: Ottmar Loos
Publisher: American Mathematical Soc.
ISBN: 0821835467
Category : Mathematics
Languages : en
Pages : 232

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Book Description
We develop the basic theory of root systems $R$ in a real vector space $X$ which are defined in analogy to the usual finite root systems, except that finiteness is replaced by local finiteness: the intersection of $R$ with every finite-dimensional subspace of $X$ is finite. The main topics are Weyl groups, parabolic subsets and positive systems, weights, and gradings.

Integral Bases for Affine Lie Algebras and Their Universal Enveloping Algebras

Integral Bases for Affine Lie Algebras and Their Universal Enveloping Algebras PDF Author: David Mitzman
Publisher: American Mathematical Soc.
ISBN: 0821850431
Category : Mathematics
Languages : en
Pages : 170

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Book Description
A revised version of the author's PhD thesis written under the supervision of J Lepowsky at Rutgers University in 1983.