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ELEMENTARY EQUIVALENCE of PROFINITE GROUPS by Moshe
ELEMENTARY EQUIVALENCE OF PROFINITE GROUPS by Moshe Jarden, Tel Aviv University∗ and Alexander Lubotzky, The Hebrew University of Jerusalem∗∗ Dedicated to Dan Segal on the occasion of his 60th birthday Abstract. There are many examples of non-isomorphic pairs of finitely generated abstract groups that are elementarily equivalent. We show that the situation in the category of profinite groups is different: If two finitely generated profinite groups are elementarily equivalent (as abstract groups), then they are isomorphic. The proof ap- plies a result of Nikolov and Segal which in turn relies on the classification of the finite simple groups. Our result does not hold any more if the profinite groups are not finitely generated. We give concrete examples of non-isomorphic profinite groups which are elementarily equivalent. MR Classification: 12E30 Directory: \Jarden\Diary\JL 3 June, 2008 * Supported by the Minkowski Center for Geometry at Tel Aviv University, established by the Minerva Foundation. ** Supported by the ISF and the Landau Center for Analysis at the Hebrew University of Jerusalem. Introduction Let L(group) be the first order language of group theory. One says that groups G and H are elementarily equivalent and writes G ≡ H if each sentence of L(group) which holds in one of these groups holds also the other one. There are many examples of pairs of elementarily equivalent groups which are not isomorphic. For example, the group Z is elementarily equivalent to every nonprincipal ultrapower of it although it is not isomorphic to it. Less trivial examples are given by the following result: If G and H are groups satisfying G × Z =∼ H × Z, then G ≡ H [Oge91] (see [Hir69] for an example of non-isomorphic groups G and H satisfying G × Z =∼ H × Z.) More generally, Nies points out in [Nie03, p. -
Abraham Robinson 1918–1974
NATIONAL ACADEMY OF SCIENCES ABRAHAM ROBINSON 1918–1974 A Biographical Memoir by JOSEPH W. DAUBEN Any opinions expressed in this memoir are those of the author and do not necessarily reflect the views of the National Academy of Sciences. Biographical Memoirs, VOLUME 82 PUBLISHED 2003 BY THE NATIONAL ACADEMY PRESS WASHINGTON, D.C. Courtesy of Yale University News Bureau ABRAHAM ROBINSON October 6, 1918–April 11, 1974 BY JOSEPH W. DAUBEN Playfulness is an important element in the makeup of a good mathematician. —Abraham Robinson BRAHAM ROBINSON WAS BORN on October 6, 1918, in the A Prussian mining town of Waldenburg (now Walbrzych), Poland.1 His father, Abraham Robinsohn (1878-1918), af- ter a traditional Jewish Talmudic education as a boy went on to study philosophy and literature in Switzerland, where he earned his Ph.D. from the University of Bern in 1909. Following an early career as a journalist and with growing Zionist sympathies, Robinsohn accepted a position in 1912 as secretary to David Wolfson, former president and a lead- ing figure of the World Zionist Organization. When Wolfson died in 1915, Robinsohn became responsible for both the Herzl and Wolfson archives. He also had become increas- ingly involved with the affairs of the Jewish National Fund. In 1916 he married Hedwig Charlotte (Lotte) Bähr (1888- 1949), daughter of a Jewish teacher and herself a teacher. 1Born Abraham Robinsohn, he later changed the spelling of his name to Robinson shortly after his arrival in London at the beginning of World War II. This spelling of his name is used throughout to distinguish Abby Robinson the mathematician from his father of the same name, the senior Robinsohn. -
Tel-Aviv University Evaluation Report
The Committee for the Evaluation of Mathematics Study-Programs Tel-Aviv University Evaluation Report August 2010 Contents Chapter 1: Background……………………………………………………………2 Chapter 2: Committee Procedures………...………………………………………3 Chapter 3: Evaluation of the School of Mathematical Sciences, Tel-Aviv University……………………………………………….......................4 Appendices: Appendix 1 – Letter of Appointment Appendix 2 - Schedule of the visit 1 Chapter 1 - Background At its meeting on October 07, 2008 the Council for Higher Education (CHE) decided to evaluate study programs in the fields of mathematics during the academic year 2009-2010. Following the decision of the CHE, the Minister of Education, who serves ex officio as a Chairperson of the CHE, appointed a Committee consisting of: • Prof. Benedict H. Gross, Mathematics Department, Harvard University, USA - Chair • Prof. Ronald Coifman, Department of Mathematics and the Department of Computer Science, Yale University, USA • Prof. Hillel Furstenberg (emeritus), Department of Mathematics, the Hebrew University, Israel • Prof. Gerard van der Geer, Korteweg-de Vries Institute for Mathematics, University of Amsterdam, the Netherlands • Prof. David Jerison1, Mathematics Departments, Massachusetts Institute of Technology, USA • Prof. Yakar Kannai, Department of Mathematics, Faculty of Mathematics and Computer Science, Weizmann Institute, Israel Ms. Noa Nof Steiner - Coordinator of the Committee on behalf of the Council for Higher Education. Within the framework of its activity, the Committee was requested to:2 1. Examine the self-evaluation reports, submitted by the institutions that provide study programs in mathematics, and to conduct on-site visits at those institutions. 2. Submit to the CHE an individual report on each of the evaluated academic units and study programs, including the Committee's findings and recommendations. -
Ranks of Abelian Varieties and the Full Mordell-Lang Conjecture In
RANKS OF ABELIAN VARIETIES AND THE FULL MORDELL-LANG CONJECTURE IN DIMENSION ONE ARNO FEHM AND SEBASTIAN PETERSEN Abstract. Let A be a non-zero abelian variety over a field F that is not algebraic over a finite field. We prove that the rational rank of the abelian group A(F ) is infinite when F is large in the sense of Pop (also called ample). The main ingredient is a deduction of the 1-dimensional case of the relative Mordell-Lang conjecture from a result of R¨ossler. 1. Introduction A considerable amount of work has been done to show that over certain fields, for example over certain infinite algebraic extensions of global fields, all abelian varieties have infinite rank. Here, the rank of an abelian variety A over a field F is the rank of the Mordell-Weil group A(F ), i.e. dimQ(A(F ) ⊗ Q). See [Ros73, FJ74, RW02, Lar03, Im06, GJ06, Pet06, IL08, IL13] to mention a few examples. In all cases known to us where one actually succeeded in proving that over a field every abelian variety has infinite rank, these fields turn out to be ample or are conjectured to be ample, where a field F is called ample (or large following [Pop96]) if every smooth F -curve C satisfies C(F ) = ∅ or |C(F )| = ∞. For example, every separably closed, real closed, or Henselian valued field is ample. See [Pop96, Jar03, Pop10, FP11] for many more examples of ample fields, and [BSF12, Pop14] for surveys on the importance and ubiquity of ample fields in contemporary Galois theory and other areas. -
Dov Jarden Born 17 January 1911 (17 Tevet, Taf Resh Ain Aleph) Deceased 29 September 1986 (25 Elul, Taf Shin Mem Vav) by Moshe Jarden12
Dov Jarden Born 17 January 1911 (17 Tevet, Taf Resh Ain Aleph) Deceased 29 September 1986 (25 Elul, Taf Shin Mem Vav) by Moshe Jarden12 http://www.dov.jarden.co.il/ 1Draft of July 9, 2018 2The author is indebted to Gregory Cherlin for translating the original biography from Hebrew and for his help to bring the biography to its present form. 1 Milestones 1911 Birth, Motele, Russian Empire (now Motal, Belarus) 1928{1933 Tachkemoni Teachers' College, Warsaw 1935 Immigration to Israel; enrolls in Hebrew University, Jerusalem: major Mathematics, minors in Bible studies and in Hebrew 1939 Marriage to Haya Urnstein, whom he called Rachel 1943 Master's degree from Hebrew University 1943{1945 Teacher, Bnei Brak 1945{1955 Completion of Ben Yehuda's dictionary under the direction of Professor Tur-Sinai 1946{1959 Editor and publisher, Riveon LeMatematika (13 volumes) 1947{1952 Assisting Abraham Even-Shoshan on Milon Hadash, a new He- brew Dictionary 1953 Publication of two Hebrew Dictionaries, the Popular Dictionary and the Pocket Dictionary, with Even-Shoshan 1956 Doctoral degree in Hebrew linguistics from Hebrew Unversity, under the direction of Professor Tur-Sinai; thesis published in 1957 1960{1962 Curator of manuscripts collection, Hebrew Union College, Cincinnati 1965 Publication of the Dictionary of Hebrew Acronyms with Shmuel Ashkenazi 1966 Publication of the Complete Hebrew-Spanish Dictionary with Arye Comay 1966 Critical edition of Samuel HaNagid's Son of Psalms under the Hebrew Union College Press imprint 1969{1973 Critical edition of -
Gershom Biography an Intellectual Scholem from Berlin to Jerusalem and Back Gershom Scholem
noam zadoff Gershom Biography An Intellectual Scholem From Berlin to Jerusalem and Back gershom scholem The Tauber Institute Series for the Study of European Jewry Jehuda Reinharz, General Editor ChaeRan Y. Freeze, Associate Editor Sylvia Fuks Fried, Associate Editor Eugene R. Sheppard, Associate Editor The Tauber Institute Series is dedicated to publishing compelling and innovative approaches to the study of modern European Jewish history, thought, culture, and society. The series features scholarly works related to the Enlightenment, modern Judaism and the struggle for emancipation, the rise of nationalism and the spread of antisemitism, the Holocaust and its aftermath, as well as the contemporary Jewish experience. The series is published under the auspices of the Tauber Institute for the Study of European Jewry —established by a gift to Brandeis University from Dr. Laszlo N. Tauber —and is supported, in part, by the Tauber Foundation and the Valya and Robert Shapiro Endowment. For the complete list of books that are available in this series, please see www.upne.com Noam Zadoff Gershom Scholem: From Berlin to Jerusalem and Back *Monika Schwarz-Friesel and Jehuda Reinharz Inside the Antisemitic Mind: The Language of Jew-Hatred in Contemporary Germany Elana Shapira Style and Seduction: Jewish Patrons, Architecture, and Design in Fin de Siècle Vienna ChaeRan Y. Freeze, Sylvia Fuks Fried, and Eugene R. Sheppard, editors The Individual in History: Essays in Honor of Jehuda Reinharz Immanuel Etkes Rabbi Shneur Zalman of Liady: The Origins of Chabad Hasidism *Robert Nemes and Daniel Unowsky, editors Sites of European Antisemitism in the Age of Mass Politics, 1880–1918 Sven-Erik Rose Jewish Philosophical Politics in Germany, 1789–1848 ChaeRan Y. -
Boolean Functions: Influence, Threshold and Noise
Boolean Functions: Influence, threshold and noise Gil Kalai∗ Abstract. This lecture studies the analysis of Boolean functions and present a few ideas, results, proofs, and problems. We start with the wider picture of expansion in graphs and then concentrate on the graph of the n-dimensional discrete cube Ωn. Boolean functions are functions from Ωn to f0; 1g. We consider the notion of the influence of variables on Boolean functions. The influence of a variable on a Boolean function is the probability that changing the value of the variable changes the value of the function. We then consider Fourier analysis of real functions on Ωn and some applications of Fourier methods. We go on to discuss connections with sharp threshold phenomena, percolation, random graphs, extremal combinatorics, correlation inequalities, and more. 2010 Mathematics Subject Classification. Primary 05-02; Secondary 05D05, 05C80. Keywords. Combinatorics, Boolean functions, Fourier methods, random graphs, perco- lation, influence, isoperimetry. 1. Prologue: German-Jewish mathematicians in the early days of the Hebrew University of Jerusalem This paper follows closely the author's lecture at the 7ECM in Berlin in July 2016. Being invited to give a plenary lecture at the ECM was a great honor and, as Keren Vogtmann said in her beautiful opening lecture on outer spaces, it was also a daunting task. I am thankful to G¨unter Ziegler for his introduction. When I ask myself in what way I am connected to the person I was thirty years ago, one answer is that it is my long-term friendship with G¨unter and other people that makes me the same person. -
Recollections of a Jewish Mathematician in Germany
Abraham A. Fraenkel Recollections of a Jewish Mathematician in Germany Edited by Jiska Cohen-Mansfi eld This portrait was photographed by Alfred Bernheim, Jerusalem, Israel. Abraham A. Fraenkel Recollections of a Jewish Mathematician in Germany Edited by Jiska Cohen-Mansfield Translated by Allison Brown Author Abraham A. Fraenkel (1891–1965) Jerusalem, Israel Editor Jiska Cohen-Mansfield Jerusalem, Israel Translated by Allison Brown ISBN 978-3-319-30845-6 ISBN 978-3-319-30847-0 (eBook) DOI 10.1007/978-3-319-30847-0 Library of Congress Control Number: 2016943130 © Springer International Publishing Switzerland 2016 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, express or implied, with respect to the material contained herein or for any errors or omissions that may have been made. -
Scientific Report for 2008
The Erwin Schr¨odingerInternational Boltzmanngasse 9/2 ESI Institute for Mathematical Physics A-1090 Vienna, Austria Scientific Report for 2008 Impressum: Eigent¨umer,Verleger, Herausgeber: The Erwin Schr¨odingerInternational Institute for Mathematical Physics, Boltzmanngasse 9, A-1090 Vienna. Redaktion: Joachim Schwermer, Jakob Yngvason Supported by the Austrian Federal Ministry of Science and Research (BMWF). Contents Preface 3 The ESI in 2008 . 5 Scientific Reports 7 Main Research Programmes . 7 Combinatorics and Statistical Physics . 7 Metastability and Rare Events in Complex Systems . 11 Hyperbolic Dynamical Systems . 17 Operator Algebras and Conformal Field Theory . 22 Workshops Organized Outside the Main Programmes . 25 Winter School in Geometry and Physics . 25 Tensor Network Methods and Entanglement in Quantum Many-Body Systems . 25 Intermetallics . 27 ESI - 15th Anniversary Celebration . 28 Frontiers in Mathematical Biology . 28 Summer School on \Combinatorics and Statistical Mechanics" . 30 Summer School on \Current Topics in Mathematical Physics" . 31 Mathematical General Relativity . 33 Mathematical Challenges in String Phenomenology . 34 Structural Probability . 37 5th Vienna Central European Seminar on Particle Physics and Quantum Field Theory: \Highlights in Computational Quantum Field Theory" . 41 Supersymmetry and Noncommutative QFT: In Memoriam Julius Wess . 42 Profinite Groups . 43 Junior Research Fellows Programme . 47 Senior Research Fellows Programme . 49 Christos N. Likos: Introduction to Theoretical Soft Matter Physics . 49 Radoslav Rashkov: Dualities between gauge theories and strings . 50 Goran Mui´c:Selected Topics in the Theory of Automorphic Forms for Reductive Groups . 51 Herbert Kurke, Denis Osipov, Alexander Zheglov . 53 Werner Ballmann . 55 Roberto Longo . 55 Seminars and Colloquia 57 ESI Preprints 67 ESI Preprints in 2008 . 67 ESI Preprints until end of February 2009 . -
Fully Hilbertian Fields 3
FULLY HILBERTIAN FIELDS LIOR BARY-SOROKER AND ELAD PARAN Abstract. We introduce the notion of fully Hilbertian fields, a strictly stronger notion than that of Hilbertian fields. We show that this class of fields exhibits the same good behavior as Hilbertian fields, but for fields of uncountable cardinality, is more natural than the notion of Hilbertian fields. In particular, we show it can be used to achieve stronger Galois theoretic results. Our proofs also provide a step toward the so-called Jarden-Lubotzky twinning principle. 1. Introduction A field K is called Hilbertian if it satisfies the following property: for every irreducible polynomial f(X,Y ) ∈ K[X,Y ] which is separable in Y , there exist infinitely many a ∈ K for which f(a, Y ) is irreducible in K[Y ]. The name Hilbertian is derived from Hilbert’s irreducibility theorem, which asserts that number fields are Hilbertian. Hilbert’s original motivation for his irreducibility theorem was the inverse Galois prob- lem. Assume one wants to realize a finite group G over a Hilbertian field K. Then given a regular Galois extension F/K(x) with group G, one can use Hilbert’s irreducibility theorem to specialize x to a ∈ K and obtain a Galois extension F¯ of K with group G. Moreover, there exist infinitely many such specialized fields, linearly disjoint over K, obtained by suitable choices of a ∈ K. Even nowadays Hilbert’s irreducibility theorem remains a cen- tral approach for the inverse Galois problem, see [16, 22]. Moreover, this theorem has numerous other applications in number theory, see e.g. -
HORIZONTAL ISOGENY THEOREMS∗ by Gerhard Frey, Essen
HORIZONTAL ISOGENY THEOREMS∗ by Gerhard Frey, Essen University and Moshe Jarden, Tel Aviv University Directory: \Works\Paper75 20 June, 2001 * Research partially supported by the Minkowski Center for Geometry at Tel Aviv Univer- sity founded by the Minerva Foundation Introduction One of the results of Tate’s celebrated article from 1966 on endomorphisms of abelian varieties over finite fields [Tat] was the isogeny theorem: Let A and A0 be abelian 0 varieties over a finite field K. If l 6= char(K) and ρA,l∞ ∼ ρA0,l∞ , then A ∼K A (see below for notation). Zarhin generalized the isogeny theorem to the case where K is finitely generated over Fp and p 6= 2. The case p = 2 was treated by Mori. Finally, one of the outcomes of Faltings’ solution of Mordell’s conjecture in 1983 was the isogeny theorem for fields which are finitely generated over Q. As a result, we know now that the isogeny theorem holds over each finitely generated field K. One may view ρA,l∞ as the limit of the representations ρA,li : Gal(K) → Aut(Ali ). It is therefore appropriate to rename the isogeny theorem as the vertical isogeny theorem. A result of Zarhin implies a horizontal isogeny theorem for abelian varieties: If the representations ρA,l and ρA0,l of Gal(K) are equivalent for infinitely 0 many prime numbers l, then A ∼K A . Our main interest in this work is elliptic curves over a finitely generated field K. 0 If E and E are elliptic curves over K and ρE,l ∼ ρE0,l for some l, then Ker(ρE,l) = 0 Ker(ρE0,l). -
The Absolute Galois Group of Subfields of the Field of Totally S-Adic Numbers∗
THE ABSOLUTE GALOIS GROUP OF SUBFIELDS OF THE FIELD OF TOTALLY S-ADIC NUMBERS∗ by Dan Haran School of Mathematics, Tel Aviv University Ramat Aviv, Tel Aviv 69978, Israel e-mail: [email protected] and Moshe Jarden School of Mathematics, Tel Aviv University Ramat Aviv, Tel Aviv 69978, Israel e-mail: [email protected] and Florian Pop Department of Mathematics, University of Pennsylvania Philadelphia, PA 19104-6395, USA e-mail: [email protected] Abstract For a finite set S of primes of a global field K and for σ1, . , σe ∈ Gal(K) we denote the field of totally S-adic numbers by Ktot,S, the fixed field of σ1, . , σe in Ktot,S by Ktot,S(σ), and the maximal Galois extension of K in Ktot,S(σ) by Ktot,S[σ]. We prove e that for almost all σ ∈ Gal(K) the absolute Galois group of Ktot,S[σ] is isomorphic to the free product of Fˆω and a free product of local factors over S. MR Classification: 12E30 Directory: \Jarden\Diary\HJPe 23 October, 2007 * Research supported by the Minkowski Center for Geometry at Tel Aviv University, estab- lished by the Minerva Foundation. Introduction The absolute Galois group Gal(K) of a global field K is a very complicated object whose structure seems to be unattainable at the present knowledge of Galois theory. What we do understand is the structure of absolute Galois Groups of certain families of infinite extensions of K of a ”semi-local type”. The present work proves what is perhaps the ultimate word in a series of results in this subject that started forty years ago.