Jeff Cheeger
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CMI Summer Schools
CMI Summer Schools 2007 Homogeneous flows, moduli spaces, and arithmetic De Giorgi Center, Pisa 2006 Arithmetic Geometry The Clay Mathematics Institute has Mathematisches Institut, conducted a program of research summer schools Georg-August-Universität, Göttingen since 2000. Designed for graduate students and PhDs within five years of their degree, the aim of 2005 Ricci Flow, 3-manifolds, and Geometry the summer schools is to furnish a new generation MSRI, Berkeley of mathematicians with the knowledge and tools needed to work successfully in an active research CMI summer schools 2004 area. Three introductory courses, each three weeks Floer Homology, Gauge Theory, and in duration, make up the core of a typical summer Low-dimensional Topology school. These are followed by one week of more Rényi Institute, Budapest advanced minicourses and individual talks. Size is limited to roughly 100 participants in order to 2003 Harmonic Analysis, Trace Formula, promote interaction and contact. Venues change and Shimura Varieties from year to year, and have ranged from Cambridge, Fields Institute, Toronto Massachusetts to Pisa, Italy. The lectures from each school are published in the CMI–AMS proceedings 2002 Geometry and String Theory series, usually within two years’ time. Newton Institute, Cambridge UK Summer Schools 2001 www.claymath.org/programs/summer_school Minimal surfaces MSRI, Berkeley Summer School Proceedings www.claymath.org/publications 2000 Mirror Symmetry Pine Manor College, Boston 2006 Arithmetic Geometry Summer School in Göttingen techniques are drawn from the theory of elliptic The 2006 summer school program will introduce curves, including modular curves and their para- participants to modern techniques and outstanding metrizations, Heegner points, and heights. -
Kähler-Einstein Metrics on Fano Manifolds. I
JOURNAL OF THE AMERICAN MATHEMATICAL SOCIETY Volume 28, Number 1, January 2015, Pages 183–197 S 0894-0347(2014)00799-2 Article electronically published on March 28, 2014 KAHLER-EINSTEIN¨ METRICS ON FANO MANIFOLDS. I: APPROXIMATION OF METRICS WITH CONE SINGULARITIES XIUXIONG CHEN, SIMON DONALDSON, AND SONG SUN 1. Introduction This is the first of a series of three articles which provide proofs of results an- nounced in [9]. Let X be a Fano manifold of complex dimension n.Letλ>0bean integer and D be a smooth divisor in the linear system |−λKX |.Forβ ∈ (0, 1) there is now a well-established notion of a K¨ahler-Einstein metric with a cone singularity of cone angle 2πβ along D. (It is often called an “edge-cone” singularity). For brevity, we will just say that ω has cone angle 2πβ along D. The Ricci curvature of such a metric ω is (1−λ(1−β))ω. Our primary concern is the case of positive Ricci −1 curvature, so we suppose throughout most of the article that β ≥ β0 > 1 − λ . However our arguments also apply to the case of non-positive Ricci curvature: see Remark 3.10. Theorem 1.1. If ω is a K¨ahler-Einstein metric with cone angle 2πβ along D with β ≥ β0,then(X, ω) is the Gromov-Hausdorff limit of a sequence of smooth K¨ahler metrics with positive Ricci curvature and with diameter bounded by a fixed number depending only on β0,λ. This suffices for most of our applications but we also prove a sharper statement. -
2019 AMS Prize Announcements
FROM THE AMS SECRETARY 2019 Leroy P. Steele Prizes The 2019 Leroy P. Steele Prizes were presented at the 125th Annual Meeting of the AMS in Baltimore, Maryland, in January 2019. The Steele Prizes were awarded to HARUZO HIDA for Seminal Contribution to Research, to PHILIppE FLAJOLET and ROBERT SEDGEWICK for Mathematical Exposition, and to JEFF CHEEGER for Lifetime Achievement. Haruzo Hida Philippe Flajolet Robert Sedgewick Jeff Cheeger Citation for Seminal Contribution to Research: Hamadera (presently, Sakai West-ward), Japan, he received Haruzo Hida an MA (1977) and Doctor of Science (1980) from Kyoto The 2019 Leroy P. Steele Prize for Seminal Contribution to University. He did not have a thesis advisor. He held po- Research is awarded to Haruzo Hida of the University of sitions at Hokkaido University (Japan) from 1977–1987 California, Los Angeles, for his highly original paper “Ga- up to an associate professorship. He visited the Institute for Advanced Study for two years (1979–1981), though he lois representations into GL2(Zp[[X ]]) attached to ordinary cusp forms,” published in 1986 in Inventiones Mathematicae. did not have a doctoral degree in the first year there, and In this paper, Hida made the fundamental discovery the Institut des Hautes Études Scientifiques and Université that ordinary cusp forms occur in p-adic analytic families. de Paris Sud from 1984–1986. Since 1987, he has held a J.-P. Serre had observed this for Eisenstein series, but there full professorship at UCLA (and was promoted to Distin- the situation is completely explicit. The methods and per- guished Professor in 1998). -
Convergence of Complete Ricci-Flat Manifolds Jiewon Park
Convergence of Complete Ricci-flat Manifolds by Jiewon Park Submitted to the Department of Mathematics in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Mathematics at the MASSACHUSETTS INSTITUTE OF TECHNOLOGY May 2020 © Massachusetts Institute of Technology 2020. All rights reserved. Author . Department of Mathematics April 17, 2020 Certified by. Tobias Holck Colding Cecil and Ida Green Distinguished Professor Thesis Supervisor Accepted by . Wei Zhang Chairman, Department Committee on Graduate Theses 2 Convergence of Complete Ricci-flat Manifolds by Jiewon Park Submitted to the Department of Mathematics on April 17, 2020, in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Mathematics Abstract This thesis is focused on the convergence at infinity of complete Ricci flat manifolds. In the first part of this thesis, we will give a natural way to identify between two scales, potentially arbitrarily far apart, in the case when a tangent cone at infinity has smooth cross section. The identification map is given as the gradient flow of a solution to an elliptic equation. We use an estimate of Colding-Minicozzi of a functional that measures the distance to the tangent cone. In the second part of this thesis, we prove a matrix Harnack inequality for the Laplace equation on manifolds with suitable curvature and volume growth assumptions, which is a pointwise estimate for the integrand of the aforementioned functional. This result provides an elliptic analogue of matrix Harnack inequalities for the heat equation or geometric flows. Thesis Supervisor: Tobias Holck Colding Title: Cecil and Ida Green Distinguished Professor 3 4 Acknowledgments First and foremost I would like to thank my advisor Tobias Colding for his continuous guidance and encouragement, and for suggesting problems to work on. -
Sam Karlin 1924—2007
Sam Karlin 1924—2007 This paper was written by Richard Olshen (Stanford University) and Burton Singer (Princeton University). It is a synthesis of written and oral contributions from seven of Karlin's former PhD students, four close colleagues, all three of his children, his wife, Dorit, and with valuable organizational assistance from Rafe Mazzeo (Chair, Department of Mathematics, Stanford University.) The contributing former PhD students were: Krishna Athreya (Iowa State University) Amir Dembo (Stanford University) Marcus Feldman (Stanford University) Thomas Liggett (UCLA) Charles Micchelli (SUNY, Albany) Yosef Rinott (Hebrew University, Jerusalem) Burton Singer (Princeton University) The contributing close colleagues were: Kenneth Arrow (Stanford University) Douglas Brutlag (Stanford University) Allan Campbell (Stanford University) Richard Olshen (Stanford University) Sam Karlin's children: Kenneth Karlin Manuel Karlin Anna Karlin Sam's wife -- Dorit Professor Samuel Karlin made fundamental contributions to game theory, analysis, mathematical statistics, total positivity, probability and stochastic processes, mathematical economics, inventory theory, population genetics, bioinformatics and biomolecular sequence analysis. He was the author or coauthor of 10 books and over 450 published papers, and received many awards and honors for his work. He was famous for his work ethic and for guiding Ph.D. students, who numbered more than 70. To describe the collection of his students as astonishing in excellence and breadth is to understate the truth of the matter. It is easy to argue—and Sam Karlin participated in many a good argument—that he was the foremost teacher of advanced students in his fields of study in the 20th Century. 1 Karlin was born in Yonova, Poland on June 8, 1924, and died at Stanford, California on December 18, 2007. -
SECTIONAL CURVATURE-TYPE CONDITIONS on METRIC SPACES 2 and Poincaré Conditions, and Even the Measure Contraction Property
SECTIONAL CURVATURE-TYPE CONDITIONS ON METRIC SPACES MARTIN KELL Abstract. In the first part Busemann concavity as non-negative curvature is introduced and a bi-Lipschitz splitting theorem is shown. Furthermore, if the Hausdorff measure of a Busemann concave space is non-trivial then the space is doubling and satisfies a Poincaré condition and the measure contraction property. Using a comparison geometry variant for general lower curvature bounds k ∈ R, a Bonnet-Myers theorem can be proven for spaces with lower curvature bound k > 0. In the second part the notion of uniform smoothness known from the theory of Banach spaces is applied to metric spaces. It is shown that Busemann functions are (quasi-)convex. This implies the existence of a weak soul. In the end properties are developed to further dissect the soul. In order to understand the influence of curvature on the geometry of a space it helps to develop a synthetic notion. Via comparison geometry sectional curvature bounds can be obtained by demanding that triangles are thinner or fatter than the corresponding comparison triangles. The two classes are called CAT (κ)- and resp. CBB(κ)-spaces. We refer to the book [BH99] and the forthcoming book [AKP] (see also [BGP92, Ots97]). Note that all those notions imply a Riemannian character of the metric space. In particular, the angle between two geodesics starting at a com- mon point is well-defined. Busemann investigated a weaker notion of non-positive curvature which also applies to normed spaces [Bus55, Section 36]. A similar idea was developed by Pedersen [Ped52] (see also [Bus55, (36.15)]). -
Uniqueness of Ricci Flow Solution on Non-Compact Manifolds and Integral Scalar Curvature Bound
Uniqueness of Ricci Flow Solution on Non-compact Manifolds and Integral Scalar Curvature Bound A Dissertation Presented by Xiaojie Wang to The Graduate School in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Mathematics Stony Brook University August 2014 Stony Brook University The Graduate School Xiaojie Wang We, the dissertation committee for the above candidate for the Doctor of Philosophy degree, hereby recommend acceptance of this dissertation. Xiuxiong Chen – Dissertation Advisor Professor, Mathematics Department Michael Anderson – Chairperson of Defense Professor, Mathematics Department Marcus Khuri Professor, Mathematics Department Xianfeng David Gu Professor, Department of Computer Science This dissertation is accepted by the Graduate School. Charles Taber Dean of the Graduate School ii Abstract of the Dissertation Uniqueness of Ricci Flow Solution on Non-compact Manifolds and Integral Scalar Curvature Bound by Xiaojie Wang Doctor of Philosophy in Mathematics Stony Brook University 2014 In this dissertation, we prove two results. The first is about the uniqueness of Ricci flow solution. B.-L. Chen and X.-P. Zhu first proved the uniqueness of Ricci flow solution to the initial value problem by assuming bilaterally bounded curvature over the space-time. Here we show that, when the initial data has bounded curvature and is non-collapsing, the complex sectional curvature bounded from below over the space-time guarantees the short-time uniqueness of solution. The second is about the integral scalar curvature bound. A. Petrunin proved that for any complete boundary free Rieman- nian manifold, if the sectional curvature is bounded from below by negative one, then the integral of the scalar curvature over any unit ball is bounded from above by a constant depending only on the dimension. -
Notices of the AMS 595 Mathematics People NEWS
NEWS Mathematics People contrast electrical impedance Takeda Awarded 2017–2018 tomography, as well as model Centennial Fellowship reduction techniques for para- bolic and hyperbolic partial The AMS has awarded its Cen- differential equations.” tennial Fellowship for 2017– Borcea received her PhD 2018 to Shuichiro Takeda. from Stanford University and Takeda’s research focuses on has since spent time at the Cal- automorphic forms and rep- ifornia Institute of Technology, resentations of p-adic groups, Rice University, the Mathemati- especially from the point of Liliana Borcea cal Sciences Research Institute, view of the Langlands program. Stanford University, and the He will use the Centennial Fel- École Normale Supérieure, Paris. Currently Peter Field lowship to visit the National Collegiate Professor of Mathematics at Michigan, she is Shuichiro Takeda University of Singapore and deeply involved in service to the applied and computa- work with Wee Teck Gan dur- tional mathematics community, in particular on editorial ing the academic year 2017–2018. boards and as an elected member of the SIAM Council. Takeda obtained a bachelor's degree in mechanical The Sonia Kovalevsky Lectureship honors significant engineering from Tokyo University of Science, master's de- contributions by women to applied or computational grees in philosophy and mathematics from San Francisco mathematics. State University, and a PhD in 2006 from the University —From an AWM announcement of Pennsylvania. After postdoctoral positions at the Uni- versity of California at San Diego, Ben-Gurion University in Israel, and Purdue University, since 2011 he has been Pardon Receives Waterman assistant and now associate professor at the University of Missouri at Columbia. -
2.1 Harmonic Map Heat Flow from a Circle
Self-shrinkers of Mean Curvature Flow and Harmonic Map Heat Flow with Rough Boundary Data by 0 TECHF 2L ' Lu Wang SEP 0 2 20 Bachelor of Science, Peking University, July 2006 LIRARIS Submitted to the Department of Mathematics ARCHNES in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the MASSACHUSETTS INSTITUTE OF TECHNOLOGY June 2011 @ Lu Wang, MMXI. All rights reserved. The author hereby grants to MIT permission to reproduce and distribute publicly paper and electronic copies of this thesis document in whole or in part. A uthor .......... ........................................... Department of Mathematics Lr'\ '~I April 19, 2011 Certified by -- ------ - ........................ Tobias H. Colding Levinson Professor of Mathematics Thesis Supervisor Accepted by 37 Bjorn Poonen Chairman, Department Committee on Graduate Students 2 Self-shrinkers of Mean Curvature Flow and Harmonic Map Heat Flow with Rough Boundary Data by Lu Wang Submitted to the Department of Mathematics on April 19, 2011, in partial fulfillment of the requirements for the degree of Doctor of Philosophy Abstract In this thesis, first, joint with Longzhi Lin, we establish estimates for the harmonic map heat flow from the unit circle into a closed manifold, and use it to construct sweepouts with the following good property: each curve in the tightened sweepout, whose energy is close to the maximal energy of curves in the sweepout, is itself close to a closed geodesic. Second, we prove the uniqueness for energy decreasing weak solutions of the har- monic map heat flow from the unit open disk into a closed manifold, given any H' initial data and boundary data, which is the restriction of the initial data on the boundary of the disk. -
1. GIT and Μ-GIT
1. GIT and µ-GIT Valentina Georgoulas Joel W. Robbin Dietmar A. Salamon ETH Z¨urich UW Madison ETH Z¨urich Dietmar did the heavy lifting; Valentina and I made him explain it to us. • A key idea comes from Xiuxiong Chen and Song Sun; they were doing an • analogous infinite dimensional problem. I learned a lot from Sean. • The 1994 edition of Mumford’s book lists 926 items in the bibliography; I • have read fewer than 900 of them. Dietmar will talk in the Geometric Analysis Seminar next Monday. • Follow the talk on your cell phone. • Calc II example of GIT: conics, eccentricity, major axis. • Many important problems in geometry can be reduced to a partial differential equation of the form µ(x)=0, where x ranges over a complexified group orbit in an infinite dimensional sym- plectic manifold X and µ : X g is an associated moment map. Here we study the finite dimensional version.→ Because we want to gain intuition for the infinite dimensional problems, our treatment avoids the structure theory of compact groups. We also generalize from projective manifolds (GIT) to K¨ahler manifolds (µ-GIT). In GIT you start with (X, J, G) and try to find Y with R(Y ) R(X)G. • ≃ In µ-GIT you start with (X,ω,G) and try to solve µ(x) = 0. • GIT = µ-GIT + rationality. • The idea is to find analogs of the GIT definitions for K¨ahler manifolds, show that the µ-GIT definitions and the GIT definitions agree for projective manifolds, and prove the analogs of the GIT theorems in the K¨ahler case. -
Council Congratulates Exxon Education Foundation
from.qxp 4/27/98 3:17 PM Page 1315 From the AMS ics. The Exxon Education Foundation funds programs in mathematics education, elementary and secondary school improvement, undergraduate general education, and un- dergraduate developmental education. —Timothy Goggins, AMS Development Officer AMS Task Force Receives Two Grants The AMS recently received two new grants in support of its Task Force on Excellence in Mathematical Scholarship. The Task Force is carrying out a program of focus groups, site visits, and information gathering aimed at developing (left to right) Edward Ahnert, president of the Exxon ways for mathematical sciences departments in doctoral Education Foundation, AMS President Cathleen institutions to work more effectively. With an initial grant Morawetz, and Robert Witte, senior program officer for of $50,000 from the Exxon Education Foundation, the Task Exxon. Force began its work by organizing a number of focus groups. The AMS has now received a second grant of Council Congratulates Exxon $50,000 from the Exxon Education Foundation, as well as a grant of $165,000 from the National Science Foundation. Education Foundation For further information about the work of the Task Force, see “Building Excellence in Doctoral Mathematics De- At the Summer Mathfest in Burlington in August, the AMS partments”, Notices, November/December 1995, pages Council passed a resolution congratulating the Exxon Ed- 1170–1171. ucation Foundation on its fortieth anniversary. AMS Pres- ident Cathleen Morawetz presented the resolution during —Timothy Goggins, AMS Development Officer the awards banquet to Edward Ahnert, president of the Exxon Education Foundation, and to Robert Witte, senior program officer with Exxon. -
Hossein Abbaspour William Abikoff Mohammed Abouzaid MIT Joe
Geometric and Algebraic Structures in Mathematics Participants, page 1 Hossein Abbaspour University of Nantes, France [email protected] William Abikoff University of Connecticut [email protected] Mohammed Abouzaid MIT [email protected] Joe Adams Stony Brook University [email protected] Seyed Ali Aleyasin Stony Brook [email protected] Michael Anderson Stony Brook [email protected] Stergios Antonakoudis Harvard University [email protected] Nikos Apostolakis Bronx Community College, CUNY [email protected] Alexander Atwood SUNY SCCC [email protected] Chris Atwood Nassau Community College [email protected] Anant Atyam Stony Brook [email protected] Artur Avila CNRS/IMPA [email protected] David Ayala Harvard University [email protected] Benjamin Balsam Stony Brook University [email protected] Claude Bardos University of Paris [email protected] Ara Basmajian Graduate Center and Hunter College, [email protected] CUNY Somnath Basu Stony Brook University [email protected] Jason Behrstock Lehman College, CUNY [email protected] Charlie Beil SCGP, Stony Brook [email protected] Olivia Bellier University of Nice [email protected] James Benn University of Notre Dame [email protected] Daniel Berwick-Evans UC Berkeley [email protected] Renato Bettiol University of Notre Dame [email protected] Chris Bishop Stony Brook University [email protected] Jonathan Bloom Columbia University [email protected] Mike Bonanno SUNY SCCC [email protected] Araceli