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Arxiv:1006.1489V2 [Math.GT] 8 Aug 2010 Ril.Ias Rfie Rmraigtesre Rils[14 Articles Survey the Reading from Profited Also I Article
Pure and Applied Mathematics Quarterly Volume 8, Number 1 (Special Issue: In honor of F. Thomas Farrell and Lowell E. Jones, Part 1 of 2 ) 1—14, 2012 The Work of Tom Farrell and Lowell Jones in Topology and Geometry James F. Davis∗ Tom Farrell and Lowell Jones caused a paradigm shift in high-dimensional topology, away from the view that high-dimensional topology was, at its core, an algebraic subject, to the current view that geometry, dynamics, and analysis, as well as algebra, are key for classifying manifolds whose fundamental group is infinite. Their collaboration produced about fifty papers over a twenty-five year period. In this tribute for the special issue of Pure and Applied Mathematics Quarterly in their honor, I will survey some of the impact of their joint work and mention briefly their individual contributions – they have written about one hundred non-joint papers. 1 Setting the stage arXiv:1006.1489v2 [math.GT] 8 Aug 2010 In order to indicate the Farrell–Jones shift, it is necessary to describe the situation before the onset of their collaboration. This is intimidating – during the period of twenty-five years starting in the early fifties, manifold theory was perhaps the most active and dynamic area of mathematics. Any narrative will have omissions and be non-linear. Manifold theory deals with the classification of ∗I thank Shmuel Weinberger and Tom Farrell for their helpful comments on a draft of this article. I also profited from reading the survey articles [14] and [4]. 2 James F. Davis manifolds. There is an existence question – when is there a closed manifold within a particular homotopy type, and a uniqueness question, what is the classification of manifolds within a homotopy type? The fifties were the foundational decade of manifold theory. -
Part III Essay on Serre's Conjecture
Serre’s conjecture Alex J. Best June 2015 Contents 1 Introduction 2 2 Background 2 2.1 Modular forms . 2 2.2 Galois representations . 6 3 Obtaining Galois representations from modular forms 13 3.1 Congruences for Ramanujan’s t function . 13 3.2 Attaching Galois representations to general eigenforms . 15 4 Serre’s conjecture 17 4.1 The qualitative form . 17 4.2 The refined form . 18 4.3 Results on Galois representations associated to modular forms 19 4.4 The level . 21 4.5 The character and the weight mod p − 1 . 22 4.6 The weight . 24 4.6.1 The level 2 case . 25 4.6.2 The level 1 tame case . 27 4.6.3 The level 1 non-tame case . 28 4.7 A counterexample . 30 4.8 The proof . 31 5 Examples 32 5.1 A Galois representation arising from D . 32 5.2 A Galois representation arising from a D4 extension . 33 6 Consequences 35 6.1 Finiteness of classes of Galois representations . 35 6.2 Unramified mod p Galois representations for small p . 35 6.3 Modularity of abelian varieties . 36 7 References 37 1 1 Introduction In 1987 Jean-Pierre Serre published a paper [Ser87], “Sur les representations´ modulaires de degre´ 2 de Gal(Q/Q)”, in the Duke Mathematical Journal. In this paper Serre outlined a conjecture detailing a precise relationship between certain mod p Galois representations and specific mod p modular forms. This conjecture and its variants have become known as Serre’s conjecture, or sometimes Serre’s modularity conjecture in order to distinguish it from the many other conjectures Serre has made. -
Roots of L-Functions of Characters Over Function Fields, Generic
Roots of L-functions of characters over function fields, generic linear independence and biases Corentin Perret-Gentil Abstract. We first show joint uniform distribution of values of Kloost- erman sums or Birch sums among all extensions of a finite field Fq, for ˆ almost all couples of arguments in Fq , as well as lower bounds on dif- ferences. Using similar ideas, we then study the biases in the distribu- tion of generalized angles of Gaussian primes over function fields and primes in short intervals over function fields, following recent works of Rudnick–Waxman and Keating–Rudnick, building on cohomological in- terpretations and determinations of monodromy groups by Katz. Our results are based on generic linear independence of Frobenius eigenval- ues of ℓ-adic representations, that we obtain from integral monodromy information via the strategy of Kowalski, which combines his large sieve for Frobenius with a method of Girstmair. An extension of the large sieve is given to handle wild ramification of sheaves on varieties. Contents 1. Introduction and statement of the results 1 2. Kloosterman sums and Birch sums 12 3. Angles of Gaussian primes 14 4. Prime polynomials in short intervals 20 5. An extension of the large sieve for Frobenius 22 6. Generic maximality of splitting fields and linear independence 33 7. Proof of the generic linear independence theorems 36 References 37 1. Introduction and statement of the results arXiv:1903.05491v2 [math.NT] 17 Dec 2019 Throughout, p will denote a prime larger than 5 and q a power of p. ˆ 1.1. Kloosterman and Birch sums. -
Equivariant Resolution of Singularities and Semi-Stable Reduction In
Equivariant Resolution of Singularities and Semi-stable Reduction in Characteristic 0 by Jianhua Wang Submitted to the Department of Mathematics in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the MASSACHUSETTS INSTITUTE OF TECHNOLOGY June 1997 © Massachusetts Institute of Technology 1997. All rights reserved. Author Department of Mathematics April 29, 1997 Certified by .-. ......................... Steven L. Kleiman Professor of Mathematics Thesis Supervisor ~ f~c\ Accepted by Richard B. Melrose, Chairman Departmental Graduate Committee Department of Mathematics JUN 2 5 1997 Equivariant Resolution of Singularities and Semi-stable Reduction in Characteristic 0 by Jianhua Wang Submitted to the Department of Mathematics on April 29, 1997, in partial fulfillment of the requirements for the degree of Doctor of Philosophy Abstract In this thesis, I shall prove the equivariant resolution of singularities theorem first, then using this theorem and the barycentric subdivision technique, I shall prove the equivariant semi-stable reduction theorem. Both results are over algebraically closed fields of characteristic 0 and their proofs are purely algebraic in nature. In the statement of the equivariant semi-stable theorem, besides giving the equivariant version of classic theorem, I shall describe more precisely what the base curve could be. I shall also discuss a stronger form of the theorem when the dimension of the fiber is less than or equal to 2. Thesis Supervisor: Steven L. Kleiman Title: Professor of Mathematics to my parents and grandparents Acknowledgments First of all I thank my thesis advisor Professor Steven Kleiman, for supporting me in all possible ways during the past three years and for imparting to me the philosophies of studying mathematics. -
Surveys in Differential Geometry
Surveys in Differential Geometry Vol. 1: Lectures given in 1990 edited by S.-T. Yau and H. Blaine Lawson Vol. 2: Lectures given in 1993 edited by C.C. Hsiung and S.-T. Yau Vol. 3: Lectures given in 1996 edited by C.C. Hsiung and S.-T. Yau Vol. 4: Integrable systems edited by Chuu Lian Terng and Karen Uhlenbeck Vol. 5: Differential geometry inspired by string theory edited by S.-T. Yau Vol. 6: Essay on Einstein manifolds edited by Claude LeBrun and McKenzie Wang Vol. 7: Papers dedicated to Atiyah, Bott, Hirzebruch, and Singer edited by S.-T. Yau Vol. 8: Papers in honor of Calabi, Lawson, Siu, and Uhlenbeck edited by S.-T. Yau Vol. 9: Eigenvalues of Laplacians and other geometric operators edited by A. Grigor’yan and S-T. Yau Vol. 10: Essays in geometry in memory of S.-S. Chern edited by S.-T. Yau Vol. 11: Metric and comparison geometry edited by Jeffrey Cheeger and Karsten Grove Vol. 12: Geometric flows edited by Huai-Dong Cao and S.-T. Yau Vol. 13: Geometry, analysis, and algebraic geometry edited by Huai-Dong Cao and S.-T.Yau Vol. 14: Geometry of Riemann surfaces and their moduli spaces edited by Lizhen Ji, Scott A. Wolpert, and S.-T. Yau Volume XIV Surveys in Differential Geometry Geometry of Riemann surfaces and their moduli spaces edited by Lizhen Ji, Scott A. Wolpert, and Shing-Tung Yau International Press www.intlpress.com Series Editor: Shing-Tung Yau Surveys in Differential Geometry, Volume 14 Geometry of Riemann surfaces and their moduli spaces Volume Editors: Lizhen Ji, University of Michigan Scott A. -
Fine Compactified Jacobians of Reduced Curves
TRANSACTIONS OF THE AMERICAN MATHEMATICAL SOCIETY Volume 369, Number 8, August 2017, Pages 5341–5402 http://dx.doi.org/10.1090/tran/6823 Article electronically published on March 6, 2017 FINE COMPACTIFIED JACOBIANS OF REDUCED CURVES MARGARIDA MELO, ANTONIO RAPAGNETTA, AND FILIPPO VIVIANI Abstract. To every singular reduced projective curve X one can associate many fine compactified Jacobians, depending on the choice of a polarization on X, each of which yields a modular compactification of a disjoint union of a finite number of copies of the generalized Jacobian of X. Weinvestigatethe geometric properties of fine compactified Jacobians focusing on curves having locally planar singularities. We give examples of nodal curves admitting non- isomorphic (and even nonhomeomorphic over the field of complex numbers) fine compactified Jacobians. We study universal fine compactified Jacobians, which are relative fine compactified Jacobians over the semiuniversal deforma- tion space of the curve X. Finally, we investigate the existence of twisted Abel maps with values in suitable fine compactified Jacobians. Contents 1. Introduction 5341 2. Fine compactified Jacobians 5349 3. Varying the polarization 5358 4. Deformation theory 5368 5. Universal fine compactified Jacobians 5373 6. Abel maps 5387 7. Examples: Locally planar curves of arithmetic genus 1 5395 Acknowledgments 5399 References 5399 1. Introduction Aim and motivation. The aim of this paper is to study fine compactified Jaco- bians of a reduced projective connected curve X over an algebraically closed field k (of arbitrary characteristic), with special emphasis on the case where X has locally planar singularities. Recall that given such a curve X,thegeneralized Jacobian J(X)ofX, defined to be the connected component of the Picard variety of X containing the identity, parametrizes line bundles on X that have multidegree zero, i.e. -
Msc Lecture: Enumerative Geometry
MSc Lecture: Enumerative Geometry Lecture by Helge Ruddat; Exercises by Tim Gräfnitz; Tu & We 16:15 – 17:45 on Zoom Description Hermann Schubert developed an effective method for solving counting problems in geometry in his book "Kalkül der abzählenden Geometrie" that appeared in 1879. A basic example is the question “how many lines in R^3 meet four given lines in general position?”. Do you know the answer? The calculus is now known as “Schubert calculus”, see (1),(2),(3). Schubert calculus is immensely powerful, e.g. you can use it to find that the number of twisted cubic curves in 3-space that are tangential to 12 quadric surfaces is 5.819.539.783.680. Even though it clearly worked, for a long time it has been unknown what the theoretical basis for the calculus truly is, i.e. nobody knew why it worked. It became the famous Hilbert problem 15 to find a theoretical basis for Schubert calculus. This was looong time ago. Today we know that intersection theory, the spaces of stable maps and Gromov-Witten theory form the right theoretical framework that underlies Schubert calculus - though there are also competing alternative approaches like Donaldson-Thomas theory. The purpose of this lecture is to introduce the basics of Gromov-Witten theory with a particular view to mirror symmetry and thus the relationship with tropical curve counting. Prerequisites When taking this class, you should have some basic understanding of algebraic geometry or complex geometry or complex analysis, that is you should either know what an algebraic variety is or know what a complex manifold or Riemann surface is. -
Fundamental Algebraic Geometry
http://dx.doi.org/10.1090/surv/123 hematical Surveys and onographs olume 123 Fundamental Algebraic Geometry Grothendieck's FGA Explained Barbara Fantechi Lothar Gottsche Luc lllusie Steven L. Kleiman Nitin Nitsure AngeloVistoli American Mathematical Society U^VDED^ EDITORIAL COMMITTEE Jerry L. Bona Peter S. Landweber Michael G. Eastwood Michael P. Loss J. T. Stafford, Chair 2000 Mathematics Subject Classification. Primary 14-01, 14C20, 13D10, 14D15, 14K30, 18F10, 18D30. For additional information and updates on this book, visit www.ams.org/bookpages/surv-123 Library of Congress Cataloging-in-Publication Data Fundamental algebraic geometry : Grothendieck's FGA explained / Barbara Fantechi p. cm. — (Mathematical surveys and monographs, ISSN 0076-5376 ; v. 123) Includes bibliographical references and index. ISBN 0-8218-3541-6 (pbk. : acid-free paper) ISBN 0-8218-4245-5 (soft cover : acid-free paper) 1. Geometry, Algebraic. 2. Grothendieck groups. 3. Grothendieck categories. I Barbara, 1966- II. Mathematical surveys and monographs ; no. 123. QA564.F86 2005 516.3'5—dc22 2005053614 Copying and reprinting. Individual readers of this publication, and nonprofit libraries acting for them, are permitted to make fair use of the material, such as to copy a chapter for use in teaching or research. Permission is granted to quote brief passages from this publication in reviews, provided the customary acknowledgment of the source is given. Republication, systematic copying, or multiple reproduction of any material in this publication is permitted only under license from the American Mathematical Society. Requests for such permission should be addressed to the Acquisitions Department, American Mathematical Society, 201 Charles Street, Providence, Rhode Island 02904-2294, USA. -
Regulators, Entropy and Infinite Determinants
Regulators, entropy and infinite determinants Christopher Deninger 1 Introduction In this note we describe instances where values of the K-theoretical regulator map evaluated on topological cycles equal entropies of topological actions by a group Γ. These entropies can also be described by determinants on the von Neu- mann algebra of Γ. There is no conceptual understanding why regulators should be related to entropies or to such determinants and it would be interesting to find an explanation. The relations were first observed for real regulators. The latter have p-adic analogues and both p-adic entropy and p-adic determinants were then defined so that similar relations hold as in the real case. We describe this p-adic theory in the second part of the paper. In fact there are two natural p-adic analogues for the relevant values of the real regulator. A purely local one which we use and a local-global one for which as yet no corresponding notions of p-adic entropy or p-adic infinite determinants exist. In both the real and p-adic cases our regulator maps are defined on subvarieties arXiv:1111.1548v1 [math.AG] 7 Nov 2011 of spec Q[Γ] where Γ = Zd. Entropy and determinants on the other hand are defined for nonabelian groups Γ as well. We explain this in some detail because it would be interesting to find a corresponding nonabelian generalization of the classical and p-adic regulator in some version of non-commutative algebraic geometry. For the Heisenberg group for example, the expected regulator values are quite explicitely known by dynamical considerations. -
SIX PROBLEMS in ALGEBRAIC DYNAMICS (UPDATED DECEMBER 2006) the Notation and Terminology Used in These Problems May Be Found in T
SIX PROBLEMS IN ALGEBRAIC DYNAMICS (UPDATED DECEMBER 2006) THOMAS WARD The notation and terminology used in these problems may be found in the lecture notes [22], and background for all of algebraic dynamics is in Schmidt’s book [19]. Problem A: order of mixing. Consider the Z2-action defined by the polynomial 2 3 4 2 4 2 f(u1, u2) = 1 + u1u2 + u1u2 + u1u2 + u1 + u2 + u1u2, (that is, the system corresponding via [14] to the module ±1 ±1 Z[u1 , u2 ]/hp, fi where p is a prime chosen to make f irreducible). The methods of [11] and [15] show that the exact order M of mixing satisfies 3 ≤ M < 7. What is it? Expanding the definitions here goes as follows. The Z2-action is the natural shift action T on the compact group 2 Z X = {x ∈ Fp | x(n,m) + x(n+1,m+1) + x(n+2,m+1) + x(n+3,m+1) +x(n+4,m) + x(n,m+2) + x(n+4,m+2) = 0 mod p for all n, m}, with a natural Haar measure µ. The order of mixing M is the largest k for which k Y lim µ (T−n1 (A1) ∩ · · · ∩ T−nk (Ak)) → µ(Ai) ni−nj →∞;i6=j i=1 for all measurable sets A1,...,Ak. Update: Considerable progress has been made on this circle of prob- lems. Masser [17] proved a conjecture of Schmidt [20] by showing that the order of mixing for an algebraic Zd by automorphisms of a zero- dimensional group as detected by studying mixing shapes coincides with the real order of mixing. -
2021 Leroy P. Steele Prizes
FROM THE AMS SECRETARY 2021 Leroy P. Steele Prizes The 2021 Leroy P. Steele Prizes were presented at the Annual Meeting of the AMS, held virtually January 6–9, 2021. Noga Alon and Joel Spencer received the Steele Prize for Mathematical Exposition. Murray Gerstenhaber was awarded the Prize for Seminal Contribution to Research. Spencer Bloch was honored with the Prize for Lifetime Achievement. Citation for Mathematical Biographical Sketch: Noga Alon Exposition: Noga Alon Noga Alon is a Professor of Mathematics at Princeton and Joel Spencer University and a Professor Emeritus of Mathematics and The 2021 Steele Prize for Math- Computer Science at Tel Aviv University, Israel. He received ematical Exposition is awarded his PhD in Mathematics at the Hebrew University of Jeru- to Noga Alon and Joel Spencer salem in 1983 and had visiting and part-time positions in for the book The Probabilistic various research institutes, including the Massachusetts Method, published by Wiley Institute of Technology, Harvard University, the Institute and Sons, Inc., in 1992. for Advanced Study in Princeton, IBM Almaden Research Now in its fourth edition, Center, Bell Laboratories, Bellcore, and Microsoft Research The Probabilistic Method is an (Redmond and Israel). He joined Tel Aviv University in invaluable toolbox for both 1985, served as the head of the School of Mathematical Noga Alon the beginner and the experi- Sciences in 1999–2001, and moved to Princeton in 2018. enced researcher in discrete He supervised more than twenty PhD students. He serves probability. It brings together on the editorial boards of more than a dozen international through one unifying perspec- technical journals and has given invited lectures in numer- tive a head-spinning variety of ous conferences, including plenary addresses in the 1996 results and methods, linked to European Congress of Mathematics and in the 2002 Inter- applications in graph theory, national Congress of Mathematicians. -
$\Mathbb {F} 1 $ for Everyone
F1 for everyone Oliver Lorscheid Abstract. This text serves as an introduction to F1-geometry for the general math- ematician. We explain the initial motivations for F1-geometry in detail, provide an overview of the different approaches to F1 and describe the main achievements of the field. Prologue F1-geometry is a recent area of mathematics that emerged from certain heuristics in combinatorics, number theory and homotopy theory that could not be explained in the frame work of Grothendieck’s scheme theory. These ideas involve a theory of algebraic geometry over a hypothetical field F1 with one element, which includes a theory of algebraic groups and their homogeneous spaces, an arithmetic curve SpecZ over F1 that compactifies the arithmetic line SpecZ and K-theory that stays in close relation to homotopy theory of topological spaces such as spheres. Starting in the mid 2000’s, there was an outburst of different approaches towards such theories, which bent and extended scheme theory. Meanwhile some of the initial problems for F1-geometry have been settled and new applications have been found, for instance in cyclic homology and tropical geometry. The first thought that crosses one’s mind in this context is probably the question: What is the “field with one element”? Obviously, this oxymoron cannot be taken literally as it would imply a mathematical contradiction. It is resolved as follows. First of all we remark that we do not need to define F1 itself—what is needed for the aims of F1-geometry is a suitable category of schemes over F1. However, many approaches contain an explicit definition of F1, and in most cases, the field with one element is not a field and has two elements.