Institute for Pure and Applied Mathematics, UCLA Annual Progress Report for 2011-2012 Award #0931852 June 3, 2013
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Amie Wilkinson 1
Amie Wilkinson 1 Amie Wilkinson Department of Mathematics, University of Chicago 5734 S. University Avenue Chicago, Illinois 60637 (773) 702-7337 [email protected] ACADEMIC POSITIONS • Professor of Mathematics, University of Chicago, 2012 { present. • Professor of Mathematics, Northwestern University, 2005 { 2012. • Associate Professor of Mathematics, Northwestern University, 2002 { 2005. • Assistant Professor of Mathematics, Northwestern University, 1999 { 2002. • Boas Assistant Professor of Mathematics, Northwestern University, 1996 { 1999. • Benjamin Peirce Instructor, Harvard University, 1995 { 1996. Visiting Positions • Visiting Professor, University of Chicago, Fall and Spring Quarters 2003{2004, Fall Quarter 2011. • Professeur Invit´e, Universit´ede Bourgogne, May 2002 and Sept 2003. • Member, Institut des Hautes Etudes Scientifiques (IHES), Summer 1993, 1996, 1998. • Visitor, IBM T.J. Watson Labs, Yorktown NY, Winter 1992 and 1994, Summer 1997, 1998, 2000, and 2001. • Graduate Research Assistant, The Center for Nonlinear Studies, Los Alamos National Laboratories, Summer, 1992. EDUCATION • Ph.D. in Mathematics, University of California, Berkeley, May 1995 • A.B. in Mathematics, Harvard University, June 1989 DATE OF BIRTH April, 1968. U.S. citizen. Amie Wilkinson 2 RESEARCH INTERESTS • Ergodic theory and smooth dynamical systems • Geometry and regularity of foliations • Actions of discrete groups on manifolds • Dynamical systems of geometric origin GRANTS, FELLOWSHIPS AND AWARDS • Levi L. Conant Prize, 2020. • Foreign Member, Academia Europaea, 2019. • Fellow of the American Mathematical Society, 2013. • Ruth Lyttle Satter Prize, 2011. • NSF Grant \Ergodicity, Rigidity, and the Interplay Between Chaotic and Regular Dynamics" $758,242, 2018{2021. • NSF Grant \Innovations in Bright Beam Science" (co-PI) $680,000, 2015{2018. • NSF Grant \RTG: Geometry and topology at the University of Chicago" (co-PI) $1,377,340, 2014{2019. -
CURRENT EVENTS BULLETIN Friday, January 8, 2016, 1:00 PM to 5:00 PM Room 4C-3 Washington State Convention Center Joint Mathematics Meetings, Seattle, WA
A MERICAN M ATHEMATICAL S OCIETY CURRENT EVENTS BULLETIN Friday, January 8, 2016, 1:00 PM to 5:00 PM Room 4C-3 Washington State Convention Center Joint Mathematics Meetings, Seattle, WA 1:00 PM Carina Curto, Pennsylvania State University What can topology tell us about the neural code? Surprising new applications of what used to be thought of as “pure” mathematics. 2:00 PM Yuval Peres, Microsoft Research and University of California, Berkeley, and Lionel Levine, Cornell University Laplacian growth, sandpiles and scaling limits Striking large-scale structure arising from simple cellular automata. 3:00 PM Timothy Gowers, Cambridge University Probabilistic combinatorics and the recent work of Peter Keevash The major existence conjecture for combinatorial designs has been proven! 4:00 PM Amie Wilkinson, University of Chicago What are Lyapunov exponents, and why are they interesting? A basic tool in understanding the predictability of physical systems, explained. Organized by David Eisenbud, Mathematical Sciences Research Institute Introduction to the Current Events Bulletin Will the Riemann Hypothesis be proved this week? What is the Geometric Langlands Conjecture about? How could you best exploit a stream of data flowing by too fast to capture? I think we mathematicians are provoked to ask such questions by our sense that underneath the vastness of mathematics is a fundamental unity allowing us to look into many different corners -- though we couldn't possibly work in all of them. I love the idea of having an expert explain such things to me in a brief, accessible way. And I, like most of us, love common-room gossip. -
I. Overview of Activities, April, 2005-March, 2006 …
MATHEMATICAL SCIENCES RESEARCH INSTITUTE ANNUAL REPORT FOR 2005-2006 I. Overview of Activities, April, 2005-March, 2006 …......……………………. 2 Innovations ………………………………………………………..... 2 Scientific Highlights …..…………………………………………… 4 MSRI Experiences ….……………………………………………… 6 II. Programs …………………………………………………………………….. 13 III. Workshops ……………………………………………………………………. 17 IV. Postdoctoral Fellows …………………………………………………………. 19 Papers by Postdoctoral Fellows …………………………………… 21 V. Mathematics Education and Awareness …...………………………………. 23 VI. Industrial Participation ...…………………………………………………… 26 VII. Future Programs …………………………………………………………….. 28 VIII. Collaborations ………………………………………………………………… 30 IX. Papers Reported by Members ………………………………………………. 35 X. Appendix - Final Reports ……………………………………………………. 45 Programs Workshops Summer Graduate Workshops MSRI Network Conferences MATHEMATICAL SCIENCES RESEARCH INSTITUTE ANNUAL REPORT FOR 2005-2006 I. Overview of Activities, April, 2005-March, 2006 This annual report covers MSRI projects and activities that have been concluded since the submission of the last report in May, 2005. This includes the Spring, 2005 semester programs, the 2005 summer graduate workshops, the Fall, 2005 programs and the January and February workshops of Spring, 2006. This report does not contain fiscal or demographic data. Those data will be submitted in the Fall, 2006 final report covering the completed fiscal 2006 year, based on audited financial reports. This report begins with a discussion of MSRI innovations undertaken this year, followed by highlights -
President's Report
Newsletter Volume 43, No. 3 • mAY–JuNe 2013 PRESIDENT’S REPORT Greetings, once again, from 35,000 feet, returning home from a major AWM conference in Santa Clara, California. Many of you will recall the AWM 40th Anniversary conference held in 2011 at Brown University. The enthusiasm generat- The purpose of the Association ed by that conference gave rise to a plan to hold a series of biennial AWM Research for Women in Mathematics is Symposia around the country. The first of these, the AWM Research Symposium 2013, took place this weekend on the beautiful Santa Clara University campus. • to encourage women and girls to study and to have active careers The symposium attracted close to 150 participants. The program included 3 plenary in the mathematical sciences, and talks, 10 special sessions on a wide variety of topics, a contributed paper session, • to promote equal opportunity and poster sessions, a panel, and a banquet. The Santa Clara campus was in full bloom the equal treatment of women and and the weather was spectacular. Thankfully, the poster sessions and coffee breaks girls in the mathematical sciences. were held outside in a courtyard or those of us from more frigid climates might have been tempted to play hooky! The event opened with a plenary talk by Maryam Mirzakhani. Mirzakhani is a professor at Stanford and the recipient of multiple awards including the 2013 Ruth Lyttle Satter Prize. Her talk was entitled “On Random Hyperbolic Manifolds of Large Genus.” She began by describing how to associate a hyperbolic surface to a graph, then proceeded with a fascinating discussion of the metric properties of surfaces associated to random graphs. -
What Are Lyapunov Exponents, and Why Are They Interesting?
BULLETIN (New Series) OF THE AMERICAN MATHEMATICAL SOCIETY Volume 54, Number 1, January 2017, Pages 79–105 http://dx.doi.org/10.1090/bull/1552 Article electronically published on September 6, 2016 WHAT ARE LYAPUNOV EXPONENTS, AND WHY ARE THEY INTERESTING? AMIE WILKINSON Introduction At the 2014 International Congress of Mathematicians in Seoul, South Korea, Franco-Brazilian mathematician Artur Avila was awarded the Fields Medal for “his profound contributions to dynamical systems theory, which have changed the face of the field, using the powerful idea of renormalization as a unifying principle.”1 Although it is not explicitly mentioned in this citation, there is a second unify- ing concept in Avila’s work that is closely tied with renormalization: Lyapunov (or characteristic) exponents. Lyapunov exponents play a key role in three areas of Avila’s research: smooth ergodic theory, billiards and translation surfaces, and the spectral theory of 1-dimensional Schr¨odinger operators. Here we take the op- portunity to explore these areas and reveal some underlying themes connecting exponents, chaotic dynamics and renormalization. But first, what are Lyapunov exponents? Let’s begin by viewing them in one of their natural habitats: the iterated barycentric subdivision of a triangle. When the midpoint of each side of a triangle is connected to its opposite vertex by a line segment, the three resulting segments meet in a point in the interior of the triangle. The barycentric subdivision of a triangle is the collection of 6 smaller triangles determined by these segments and the edges of the original triangle: Figure 1. Barycentric subdivision. Received by the editors August 2, 2016. -
Boshernitzan's Condition, Factor Complexity, and an Application
BOSHERNITZAN’S CONDITION, FACTOR COMPLEXITY, AND AN APPLICATION VAN CYR AND BRYNA KRA Abstract. Boshernitzan found a decay condition on the measure of cylin- der sets that implies unique ergodicity for minimal subshifts. Interest in the properties of subshifts satisfying this condition has grown recently, due to a connection with the study of discrete Schr¨odinger operators. Of particular interest is the question of how restrictive Boshernitzan’s condition is. While it implies zero topological entropy, our main theorem shows how to construct minimal subshifts satisfying the condition whose factor complexity grows faster than any pre-assigned subexponential rate. As an application, via a theorem of Damanik and Lenz, we show that there is no subexponentially growing se- quence for which the spectra of all discrete Schr¨odinger operators associated with subshifts whose complexity grows faster than the given sequence, have only finitely many gaps. 1. Boshernitzan’s complexity conditions For a symbolic dynamical system (X, σ), many of the isomorphism invariants we have are statements about the growth rate of the word complexity function PX (n), which counts the number of distinct cylinder sets determined by words of length n having nonempty intersection with X. For example, the exponential growth of PX (n) is the topological entropy of (X, σ), while the linear growth rate of PX (n) gives an invariant to begin distinguishing between zero entropy systems. Of course there are different senses in which the growth of PX (n) could be said to be linear and different invariants arise from them. For example, one can consider systems with linear limit inferior growth, meaning lim infn→∞ PX (n)/n < ∞, or the stronger condition of linear limit superior growth, meaning lim supn→∞ PX (n)/n < ∞. -
Stable Accessibility Is C1 Dense
Stable accessibility is C1 dense Dmitry Dolgopyat and Amie Wilkinson August 27, 2003 Abstract We prove that in the space of all C r (r ≥ 1) partially hyperbolic diffeomorphisms, there is a C 1 open and dense set of accessible dif- feomorphisms. This settles the C 1 case of a conjecture of Pugh and Shub. The same result holds in the space of volume preserving or symplectic partially hyperbolic diffeomorphisms. Combining this theorem with results in [Br], [Ar] and [PugSh3], we obtain several corollaries. The first states that in the space of volume preserving or symplectic partially hyperbolic diffeomorphisms, topological transitivity holds on an open and dense set. Further, on a symplectic n-manifold (n ≤ 4) the C 1-closure of the stably transitive symplectomorphisms is precisely the closure of the partially hyperbolic symplectomorphisms. Finally, stable ergodicity is C 1 open and dense among the volume preserving, partially hyperbolic diffeomorphisms satisfying the additional technical hypotheses of [PugSh3] . Introduction This paper is about the accessibility property of partially hyperbolic diffeo- morphisms. We show that accessibility holds for a C1 open and dense set in the space of all partially hyperbolic diffeomorphisms, thus settling the C1 version of a conjecture of Pugh and Shub [PugSh1]. Partially hyper- bolic diffeomorphisms are similar to Anosov diffeomorphisms, in that they possess invariant hyperbolic directions, but unlike Anosov diffeomorphisms, they can also possess invariant directions of non-hyperbolic behavior. Ac- cessibility means that the hyperbolic directions fill up the manifold on a macroscopic scale. Accessibility often provides enough hyperbolicity for a 1 variety of chaotic properties, such as topological transitivity [Br] and ergod- icity [PugSh3], to hold. -
Read Press Release
The Work of Artur Avila Artur Avila has made outstanding contributions to dynamical systems, analysis, and other areas, in many cases proving decisive results that solved long-standing open problems. A native of Brazil who spends part of his time there and part in France, he combines the strong mathematical cultures and traditions of both countries. Nearly all his work has been done through collaborations with some 30 mathematicians around the world. To these collaborations Avila brings formidable technical power, the ingenuity and tenacity of a master problem-solver, and an unerring sense for deep and significant questions. Avila's achievements are many and span a broad range of topics; here we focus on only a few highlights. One of his early significant results closes a chapter on a long story that started in the 1970s. At that time, physicists, most notably Mitchell Feigenbaum, began trying to understand how chaos can arise out of very simple systems. Some of the systems they looked at were based on iterating a mathematical rule such as 3x(1−x). Starting with a given point, one can watch the trajectory of the point under repeated applications of the rule; one can think of the rule as moving the starting point around over time. For some maps, the trajectories eventually settle into stable orbits, while for other maps the trajectories become chaotic. Out of the drive to understand such phenomena grew the subject of discrete dynamical systems, to which scores of mathematicians contributed in the ensuing decades. Among the central aims was to develop ways to predict long-time behavior. -
AMS Officers and Committee Members
Officers and Committee Members Numbers to the left of headings are used as points of reference 2. Council in an index to AMS committees which follows this listing. Primary and secondary headings are: 2.0.1. Officers of the AMS 1. Officers President James G. Glimm 2008 1.1. Liaison Committee President Elect George E. Andrews 2008 2. Council Vice President Robert L. Bryant 2009 2.1. Executive Committee of the Council 3. Board of Trustees Ruth M. Charney 2008 4. Committees Bernd Sturmfels 2010 4.1. Committees of the Council Secretary Robert J. Daverman 2008 4.2. Editorial Committees Associate Secretaries* Susan J. Friedlander 2009 4.3. Committees of the Board of Trustees Michel L. Lapidus 2009 4.4. Committees of the Executive Committee and Board of Matthew Miller 2008 Trustees Lesley M. Sibner 2008 4.5. Internal Organization of the AMS 4.6. Program and Meetings Treasurer John M. Franks 2008 4.7. Status of the Profession Associate Treasurer Donald E. McClure 2008 4.8. Prizes and Awards 4.9. Institutes and Symposia 4.10. Joint Committees 2.0.2. Representatives of Committees 5. Representatives Bulletin Susan J. Friedlander 2008 6. Index Colloquium Paul J. Sally Jr. 2011 Terms of members expire on January 31 following the year given Executive Committee Sylvain E. Cappell 2009 unless otherwise specified. Journal of the AMS Robert K. Lazarsfeld 2009 Mathematical Reviews Jonathan I. Hall 2008 Mathematical Surveys 1. Officers and Monographs J. Tobias Stafford 2008 Mathematics of President James G. Glimm 2008 Computation Chi-Wang Shu 2011 President Elect George E. -
Attractors and Orbit-Flip Homoclinic Orbits for Star Flows
PROCEEDINGS OF THE AMERICAN MATHEMATICAL SOCIETY Volume 141, Number 8, August 2013, Pages 2783–2791 S 0002-9939(2013)11535-2 Article electronically published on April 12, 2013 ATTRACTORS AND ORBIT-FLIP HOMOCLINIC ORBITS FOR STAR FLOWS C. A. MORALES (Communicated by Bryna Kra) Abstract. We study star flows on closed 3-manifolds and prove that they either have a finite number of attractors or can be C1 approximated by vector fields with orbit-flip homoclinic orbits. 1. Introduction The notion of attractor deserves a fundamental place in the modern theory of dynamical systems. This assertion, supported by the nowadays classical theory of turbulence [27], is enlightened by the recent Palis conjecture [24] about the abun- dance of dynamical systems with finitely many attractors absorbing most positive trajectories. If confirmed, such a conjecture means the understanding of a great part of dynamical systems in the sense of their long-term behaviour. Here we attack a problem which goes straight to the Palis conjecture: The fini- tude of the number of attractors for a given dynamical system. Such a problem has been solved positively under certain circunstances. For instance, we have the work by Lopes [16], who, based upon early works by Ma˜n´e [18] and extending pre- vious ones by Liao [15] and Pliss [25], studied the structure of the C1 structural stable diffeomorphisms and proved the finitude of attractors for such diffeomor- phisms. His work was largely extended by Ma˜n´e himself in the celebrated solution of the C1 stability conjecture [17]. On the other hand, the Japanesse researchers S. -
The Abel Prize Laureate 2017
The Abel Prize Laureate 2017 Yves Meyer École normale supérieure Paris-Saclay, France www.abelprize.no Yves Meyer receives the Abel Prize for 2017 “for his pivotal role in the development of the mathematical theory of wavelets.” Citation The Abel Committee The Norwegian Academy of Science and or “wavelets”, obtained by both dilating infinite sequence of nested subspaces Meyer’s expertise in the mathematics Letters has decided to award the Abel and translating a fixed function. of L2(R) that satisfy a few additional of the Calderón-Zygmund school that Prize for 2017 to In the spring of 1985, Yves Meyer invariance properties. This work paved opened the way for the development of recognised that a recovery formula the way for the construction by Ingrid wavelet theory, providing a remarkably Yves Meyer, École normale supérieure found by Morlet and Alex Grossmann Daubechies of orthonormal bases of fruitful link between a problem set Paris-Saclay, France was an identity previously discovered compactly supported wavelets. squarely in pure mathematics and a theory by Alberto Calderón. At that time, Yves In the following decades, wavelet with wide applicability in the real world. “for his pivotal role in the Meyer was already a leading figure analysis has been applied in a wide development of the mathematical in the Calderón-Zygmund theory of variety of arenas as diverse as applied theory of wavelets.” singular integral operators. Thus began and computational harmonic analysis, Meyer’s study of wavelets, which in less data compression, noise reduction, Fourier analysis provides a useful way than ten years would develop into a medical imaging, archiving, digital cinema, of decomposing a signal or function into coherent and widely applicable theory. -
On the Ergodicity of Partially Hyperbolic Systems
ANNALS OF MATHEMATICS On the ergodicity of partially hyperbolic systems By Keith Burns and Amie Wilkinson SECOND SERIES, VOL. 171, NO. 1 January, 2010 anmaah Annals of Mathematics, 171 (2010), 451–489 On the ergodicity of partially hyperbolic systems By KEITH BURNS and AMIE WILKINSON Abstract Pugh and Shub have conjectured that essential accessibility implies ergodicity for a C 2, partially hyperbolic, volume-preserving diffeomorphism. We prove this conjecture under a mild center bunching assumption, which is satisfied in particular by all partially hyperbolic systems with 1-dimensional center bundle. We also 1 ı obtain ergodicity results for C C partially hyperbolic systems. Introduction In[Hop39], Eberhard Hopf introduced a simple argument that proved the ergodicity (with respect to Liouville measure) of the geodesic flow of a compact, negatively curved surface. The argument has since been applied to increasingly general classes of dynamical systems. The key feature that these systems possess is hyperbolicity. The strongest form of hyperbolicity is uniform hyperbolicity. A diffeomorphism f M M of a compact manifold M is uniformly hyperbolic or W ! Anosov if there exists a splitting of the tangent bundle into Tf -invariant subbundles, given by TM Es Eu; D ˚ and a continuous Riemannian metric such that, for every unit vector v TM , 2 Tf v < 1 if v Es; k k 2 Tf v > 1 if v Eu: k k 2 Anosov flows are defined similarly, with Es Eu complementary to the bundle ˚ E0 that is tangent to the flow direction. The bundles Es and Eu of an Anosov system are tangent to the stable and unstable foliations ᐃs and ᐃu, respectively.