Table of Contents of EGA I–IV Chapter 0. Preliminaries (In Volume I) §1
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Multiplicative Theory of Ideals This Is Volume 43 in PURE and APPLIED MATHEMATICS a Series of Monographs and Textbooks Editors: PAULA
Multiplicative Theory of Ideals This is Volume 43 in PURE AND APPLIED MATHEMATICS A Series of Monographs and Textbooks Editors: PAULA. SMITHAND SAMUELEILENBERG A complete list of titles in this series appears at the end of this volume MULTIPLICATIVE THEORY OF IDEALS MAX D. LARSEN / PAUL J. McCARTHY University of Nebraska University of Kansas Lincoln, Nebraska Lawrence, Kansas @ A CADEM I C P RE S S New York and London 1971 COPYRIGHT 0 1971, BY ACADEMICPRESS, INC. ALL RIGHTS RESERVED NO PART OF THIS BOOK MAY BE REPRODUCED IN ANY FORM, BY PHOTOSTAT, MICROFILM, RETRIEVAL SYSTEM, OR ANY OTHER MEANS, WITHOUT WRITTEN PERMISSION FROM THE PUBLISHERS. ACADEMIC PRESS, INC. 111 Fifth Avenue, New York, New York 10003 United Kingdom Edition published by ACADEMIC PRESS, INC. (LONDON) LTD. Berkeley Square House, London WlX 6BA LIBRARY OF CONGRESS CATALOG CARD NUMBER: 72-137621 AMS (MOS)1970 Subject Classification 13F05; 13A05,13B20, 13C15,13E05,13F20 PRINTED IN THE UNITED STATES OF AMERICA To Lillie and Jean This Page Intentionally Left Blank Contents Preface xi ... Prerequisites Xlll Chapter I. Modules 1 Rings and Modules 1 2 Chain Conditions 8 3 Direct Sums 12 4 Tensor Products 15 5 Flat Modules 21 Exercises 27 Chapter II. Primary Decompositions and Noetherian Rings 1 Operations on Ideals and Submodules 36 2 Primary Submodules 39 3 Noetherian Rings 44 4 Uniqueness Results for Primary Decompositions 48 Exercises 52 Chapter Ill. Rings and Modules of Quotients 1 Definition 61 2 Extension and Contraction of Ideals 66 3 Properties of Rings of Quotients 71 Exercises 74 Vii Vlll CONTENTS Chapter IV. -
Derived Categories. Winter 2008/09
Derived categories. Winter 2008/09 Igor V. Dolgachev May 5, 2009 ii Contents 1 Derived categories 1 1.1 Abelian categories .......................... 1 1.2 Derived categories .......................... 9 1.3 Derived functors ........................... 24 1.4 Spectral sequences .......................... 38 1.5 Exercises ............................... 44 2 Derived McKay correspondence 47 2.1 Derived category of coherent sheaves ................ 47 2.2 Fourier-Mukai Transform ...................... 59 2.3 Equivariant derived categories .................... 75 2.4 The Bridgeland-King-Reid Theorem ................ 86 2.5 Exercises ............................... 100 3 Reconstruction Theorems 105 3.1 Bondal-Orlov Theorem ........................ 105 3.2 Spherical objects ........................... 113 3.3 Semi-orthogonal decomposition ................... 121 3.4 Tilting objects ............................ 128 3.5 Exercises ............................... 131 iii iv CONTENTS Lecture 1 Derived categories 1.1 Abelian categories We assume that the reader is familiar with the concepts of categories and func- tors. We will assume that all categories are small, i.e. the class of objects Ob(C) in a category C is a set. A small category can be defined by two sets Mor(C) and Ob(C) together with two maps s, t : Mor(C) → Ob(C) defined by the source and the target of a morphism. There is a section e : Ob(C) → Mor(C) for both maps defined by the identity morphism. We identify Ob(C) with its image under e. The composition of morphisms is a map c : Mor(C) ×s,t Mor(C) → Mor(C). There are obvious properties of the maps (s, t, e, c) expressing the axioms of associativity and the identity of a category. For any A, B ∈ Ob(C) we denote −1 −1 by MorC(A, B) the subset s (A) ∩ t (B) and we denote by idA the element e(A) ∈ MorC(A, A). -
Representations of Semisimple Lie Algebras in Prime Characteristic and the Noncommutative Springer Resolution
Annals of Mathematics 178 (2013), 835{919 http://dx.doi.org/10.4007/annals.2013.178.3.2 Representations of semisimple Lie algebras in prime characteristic and the noncommutative Springer resolution By Roman Bezrukavnikov and Ivan Mirkovic´ To Joseph Bernstein with admiration and gratitude Abstract We prove most of Lusztig's conjectures on the canonical basis in homol- ogy of a Springer fiber. The conjectures predict that this basis controls numerics of representations of the Lie algebra of a semisimple algebraic group over an algebraically closed field of positive characteristic. We check this for almost all characteristics. To this end we construct a noncom- mutative resolution of the nilpotent cone which is derived equivalent to the Springer resolution. On the one hand, this noncommutative resolution is closely related to the positive characteristic derived localization equiva- lences obtained earlier by the present authors and Rumynin. On the other hand, it is compatible with the t-structure arising from an equivalence with the derived category of perverse sheaves on the affine flag variety of the Langlands dual group. This equivalence established by Arkhipov and the first author fits the framework of local geometric Langlands duality. The latter compatibility allows one to apply Frobenius purity theorem to deduce the desired properties of the basis. We expect the noncommutative counterpart of the Springer resolution to be of independent interest from the perspectives of algebraic geometry and geometric Langlands duality. Contents 0. Introduction 837 0.1. Notations and conventions 841 1. t-structures on cotangent bundles of flag varieties: statements and preliminaries 842 R.B. -
Commutative Algebra, Lecture Notes
COMMUTATIVE ALGEBRA, LECTURE NOTES P. SOSNA Contents 1. Very brief introduction 2 2. Rings and Ideals 2 3. Modules 10 3.1. Tensor product of modules 15 3.2. Flatness 18 3.3. Algebras 21 4. Localisation 22 4.1. Local properties 25 5. Chain conditions, Noetherian and Artin rings 29 5.1. Noetherian rings and modules 31 5.2. Artin rings 36 6. Primary decomposition 38 6.1. Primary decompositions in Noetherian rings 42 6.2. Application to Artin rings 43 6.3. Some geometry 44 6.4. Associated primes 45 7. Ring extensions 49 7.1. More geometry 56 8. Dimension theory 57 8.1. Regular rings 66 9. Homological methods 68 9.1. Recollections 68 9.2. Global dimension 71 9.3. Regular sequences, global dimension and regular rings 76 10. Differentials 83 10.1. Construction and some properties 83 10.2. Connection to regularity 88 11. Appendix: Exercises 91 References 100 1 2 P. SOSNA 1. Very brief introduction These are notes for a lecture (14 weeks, 2×90 minutes per week) held at the University of Hamburg in the winter semester 2014/2015. The goal is to introduce and study some basic concepts from commutative algebra which are indispensable in, for instance, algebraic geometry. There are many references for the subject, some of them are in the bibliography. In Sections 2-8 I mostly closely follow [2], sometimes rearranging the order in which the results are presented, sometimes omitting results and sometimes giving statements which are missing in [2]. In Section 9 I mostly rely on [9], while most of the material in Section 10 closely follows [4]. -
Change of Rings Theorems
CHANG E OF RINGS THEOREMS CHANGE OF RINGS THEOREMS By PHILIP MURRAY ROBINSON, B.SC. A Thesis Submitted to the School of Graduate Studies in Partial Fulfilment of the Requirements for the Degree Master of Science McMaster University (July) 1971 MASTER OF SCIENCE (1971) l'v1cHASTER UNIVERSITY {Mathematics) Hamilton, Ontario TITLE: Change of Rings Theorems AUTHOR: Philip Murray Robinson, B.Sc. (Carleton University) SUPERVISOR: Professor B.J.Mueller NUMBER OF PAGES: v, 38 SCOPE AND CONTENTS: The intention of this thesis is to gather together the results of various papers concerning the three change of rings theorems, generalizing them where possible, and to determine if the various results, although under different hypotheses, are in fact, distinct. {ii) PREFACE Classically, there exist three theorems which relate the two homological dimensions of a module over two rings. We deal with the first and last of these theorems. J. R. Strecker and L. W. Small have significantly generalized the "Third Change of Rings Theorem" and we have simply re organized their results as Chapter 2. J. M. Cohen and C. u. Jensen have generalized the "First Change of Rings Theorem", each with hypotheses seemingly distinct from the other. However, as Chapter 3 we show that by developing new proofs for their theorems we can, indeed, generalize their results and by so doing show that their hypotheses coincide. Some examples due to Small and Cohen make up Chapter 4 as a completion to the work. (iii) ACKNOW-EDGMENTS The author expresses his sincere appreciation to his supervisor, Dr. B. J. Mueller, whose guidance and helpful criticisms were of greatest value in the preparation of this thesis. -
October 2013
LONDONLONDON MATHEMATICALMATHEMATICAL SOCIETYSOCIETY NEWSLETTER No. 429 October 2013 Society MeetingsSociety 2013 ELECTIONS voting the deadline for receipt of Meetings TO COUNCIL AND votes is 7 November 2013. and Events Members may like to note that and Events NOMINATING the LMS Election blog, moderated 2013 by the Scrutineers, can be found at: COMMITTEE http://discussions.lms.ac.uk/ Thursday 31 October The LMS 2013 elections will open on elections2013/. Good Practice Scheme 10th October 2013. LMS members Workshop, London will be contacted directly by the Future elections page 15 Electoral Reform Society (ERS), who Members are invited to make sug- Friday 15 November will send out the election material. gestions for nominees for future LMS Graduate Student In advance of this an email will be elections to Council. These should Meeting, London sent by the Society to all members be addressed to Dr Penny Davies 1 page 4 who are registered for electronic who is the Chair of the Nominat- communication informing them ing Committee (nominations@lms. Friday 15 November that they can expect to shortly re- ac.uk). Members may also make LMS AGM, London ceive some election correspondence direct nominations: details will be page 5 from the ERS. published in the April 2014 News- Monday 16 December Those not registered to receive letter or are available from Duncan SW & South Wales email correspondence will receive Turton at the LMS (duncan.turton@ Regional Meeting, all communications in paper for- lms.ac.uk). Swansea mat, both from the Society and 18-21 December from the ERS. Members should ANNUAL GENERAL LMS Prospects in check their post/email regularly in MEETING Mathematics, Durham October for communications re- page 11 garding the elections. -
Topics in Noncommutative Algebraic Geometry, Homological Algebra and K-Theory
Topics in Noncommutative Algebraic Geometry, Homological Algebra and K-Theory Introduction This text is based on my lectures delivered at the School on Algebraic K-Theory and Applications which took place at the International Center for Theoretical Physics (ICTP) in Trieste during the last two weeks of May of 2007. It might be regarded as an introduction to some basic facts of noncommutative algebraic geometry and the related chapters of homological algebra and (as a part of it) a non-conventional version of higher K-theory of noncommutative 'spaces'. Arguments are mostly replaced by sketches of the main steps, or references to complete proofs, which makes the text an easier reading than the ample accounts on different topics discussed here indicated in the bibliography. Lecture 1 is dedicated to the first notions of noncommutative algebraic geometry { preliminaries on 'spaces' represented by categories and morphisms of 'spaces' represented by (isomorphism classes of) functors. We introduce continuous, affine, and locally affine morphisms which lead to definitions of noncommutative schemes and more general locally affine 'spaces'. The notion of a noncommutative scheme is illustrated with important examples related to quantized enveloping algebras: the quantum base affine spaces and flag varieties and the associated quantum D-schemes represented by the categories of (twisted) quantum D-modules introduced in [LR] (see also [T]). Noncommutative projective 'spaces' introduced in [KR1] and more general Grassmannians and flag varieties studied in [KR3] are examples of smooth locally affine noncommutative 'spaces' which are not schemes. In Lecture 2, we recover some fragments of geometry behind the pseudo-geometric picture outlined in the first lecture. -
Topics in Module Theory
Chapter 7 Topics in Module Theory This chapter will be concerned with collecting a number of results and construc- tions concerning modules over (primarily) noncommutative rings that will be needed to study group representation theory in Chapter 8. 7.1 Simple and Semisimple Rings and Modules In this section we investigate the question of decomposing modules into \simpler" modules. (1.1) De¯nition. If R is a ring (not necessarily commutative) and M 6= h0i is a nonzero R-module, then we say that M is a simple or irreducible R- module if h0i and M are the only submodules of M. (1.2) Proposition. If an R-module M is simple, then it is cyclic. Proof. Let x be a nonzero element of M and let N = hxi be the cyclic submodule generated by x. Since M is simple and N 6= h0i, it follows that M = N. ut (1.3) Proposition. If R is a ring, then a cyclic R-module M = hmi is simple if and only if Ann(m) is a maximal left ideal. Proof. By Proposition 3.2.15, M =» R= Ann(m), so the correspondence the- orem (Theorem 3.2.7) shows that M has no submodules other than M and h0i if and only if R has no submodules (i.e., left ideals) containing Ann(m) other than R and Ann(m). But this is precisely the condition for Ann(m) to be a maximal left ideal. ut (1.4) Examples. (1) An abelian group A is a simple Z-module if and only if A is a cyclic group of prime order. -
Splitting of Vector Bundles on Punctured Spectrum of Regular Local Rings
City University of New York (CUNY) CUNY Academic Works All Dissertations, Theses, and Capstone Projects Dissertations, Theses, and Capstone Projects 2005 Splitting of Vector Bundles on Punctured Spectrum of Regular Local Rings Mahdi Majidi-Zolbanin Graduate Center, City University of New York How does access to this work benefit ou?y Let us know! More information about this work at: https://academicworks.cuny.edu/gc_etds/1765 Discover additional works at: https://academicworks.cuny.edu This work is made publicly available by the City University of New York (CUNY). Contact: [email protected] Splitting of Vector Bundles on Punctured Spectrum of Regular Local Rings by Mahdi Majidi-Zolbanin A dissertation submitted to the Graduate Faculty in Mathematics in partial fulfillment of the requirements for the degree of Doctor of Philosophy, The City University of NewYork. 2005 UMI Number: 3187456 Copyright 2005 by Majidi-Zolbanin, Mahdi All rights reserved. UMI Microform 3187456 Copyright 2005 by ProQuest Information and Learning Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. ProQuest Information and Learning Company 300 North Zeeb Road P.O. Box 1346 Ann Arbor, MI 48106-1346 ii c 2005 Mahdi Majidi-Zolbanin All Rights Reserved iii This manuscript has been read and accepted for the Graduate Faculty in Mathematics in satisfaction of the dissertation requirements for the degree of Doctor of Philosophy. Lucien Szpiro Date Chair of Examining Committee Jozek Dodziuk Date Executive Officer Lucien Szpiro Raymond Hoobler Alphonse Vasquez Ian Morrison Supervisory Committee THE CITY UNIVERSITY OF NEW YORK iv Abstract Splitting of Vector Bundles on Punctured Spectrum of Regular Local Rings by Mahdi Majidi-Zolbanin Advisor: Professor Lucien Szpiro In this dissertation we study splitting of vector bundles of small rank on punctured spectrum of regular local rings. -
Depth, Dimension and Resolutions in Commutative Algebra
Depth, Dimension and Resolutions in Commutative Algebra Claire Tête PhD student in Poitiers MAP, May 2014 Claire Tête Commutative Algebra This morning: the Koszul complex, regular sequence, depth Tomorrow: the Buchsbaum & Eisenbud criterion and the equality of Aulsander & Buchsbaum through examples. Wednesday: some elementary results about the homology of a bicomplex Claire Tête Commutative Algebra I will begin with a little example. Let us consider the ideal a = hX1, X2, X3i of A = k[X1, X2, X3]. What is "the" resolution of A/a as A-module? (the question is deliberatly not very precise) Claire Tête Commutative Algebra I will begin with a little example. Let us consider the ideal a = hX1, X2, X3i of A = k[X1, X2, X3]. What is "the" resolution of A/a as A-module? (the question is deliberatly not very precise) We would like to find something like this dm dm−1 d1 · · · Fm Fm−1 · · · F1 F0 A/a with A-modules Fi as simple as possible and s.t. Im di = Ker di−1. Claire Tête Commutative Algebra I will begin with a little example. Let us consider the ideal a = hX1, X2, X3i of A = k[X1, X2, X3]. What is "the" resolution of A/a as A-module? (the question is deliberatly not very precise) We would like to find something like this dm dm−1 d1 · · · Fm Fm−1 · · · F1 F0 A/a with A-modules Fi as simple as possible and s.t. Im di = Ker di−1. We say that F· is a resolution of the A-module A/a Claire Tête Commutative Algebra I will begin with a little example. -
Reflexivity Revisited
REFLEXIVITY REVISITED MOHSEN ASGHARZADEH ABSTRACT. We study some aspects of reflexive modules. For example, we search conditions for which reflexive modules are free or close to free modules. 1. INTRODUCTION In this note (R, m, k) is a commutative noetherian local ring and M is a finitely generated R- module, otherwise specializes. The notation stands for a general module. For simplicity, M the notation ∗ stands for HomR( , R). Then is called reflexive if the natural map ϕ : M M M M is bijection. Finitely generated projective modules are reflexive. In his seminal paper M→M∗∗ Kaplansky proved that projective modules (over local rings) are free. The local assumption is really important: there are a lot of interesting research papers (even books) on the freeness of projective modules over polynomial rings with coefficients from a field. In general, the class of reflexive modules is extremely big compared to the projective modules. As a generalization of Seshadri’s result, Serre observed over 2-dimensional regular local rings that finitely generated reflexive modules are free in 1958. This result has some applications: For instance, in the arithmetical property of Iwasawa algebras (see [45]). It seems freeness of reflexive modules is subtle even over very special rings. For example, in = k[X,Y] [29, Page 518] Lam says that the only obvious examples of reflexive modules over R : (X,Y)2 are the free modules Rn. Ramras posed the following: Problem 1.1. (See [19, Page 380]) When are finitely generated reflexive modules free? Over quasi-reduced rings, problem 1.1 was completely answered (see Proposition 4.22). -
ON SUPPORTS and ASSOCIATED PRIMES of MODULES OVER the ENVELOPING ALGEBRAS of NILPOTENT LIE ALGEBRAS Introduction Let G Be a Conn
TRANSACTIONS OF THE AMERICAN MATHEMATICAL SOCIETY Volume 353, Number 6, Pages 2131{2170 S 0002-9947(01)02741-6 Article electronically published on January 3, 2001 ON SUPPORTS AND ASSOCIATED PRIMES OF MODULES OVER THE ENVELOPING ALGEBRAS OF NILPOTENT LIE ALGEBRAS BORIS SIROLAˇ Abstract. Let n be a nilpotent Lie algebra, over a field of characteristic zero, and U its universal enveloping algebra. In this paper we study: (1) the prime ideal structure of U related to finitely generated U-modules V ,andin particular the set Ass V of associated primes for such V (note that now Ass V is equal to the set Annspec V of annihilator primes for V ); (2) the problem of nontriviality for the modules V=PV when P is a (maximal) prime of U,andin particular when P is the augmentation ideal Un of U. We define the support of V , as a natural generalization of the same notion from commutative theory, and show that it is the object of primary interest when dealing with (2). We also introduce and study the reduced localization and the reduced support, which enables to better understand the set Ass V . Weprovethefollowing generalization of a stability result given by W. Casselman and M. S. Osborne inthecasewhenN, N as in the theorem, are abelian. We also present some of its interesting consequences. Theorem. Let Q be a finite-dimensional Lie algebra over a field of char- acteristic zero, and N an ideal of Q;denotebyU(N) the universal enveloping algebra of N.LetV be a Q-module which is finitely generated as an N-module.