CMSA

Inequality Aversion, Populism, and the Backlash Against Globalization
2019-04-10 14:30 - 15:30 (America/New_York) | CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Speaker: Pietro Veronesi (University of Chicago)
Title: Inequality Aversion, Populism, and the Backlash Against Globalization
Abstract: Motivated by the recent rise of populism in western democracies, we develop a model in which a populist backlash emerges endogenously in a growing economy. In the model, voters dislike inequality, especially the high consumption of “elites.” Economic growth exacerbates inequality due to heterogeneity in risk aversion. In response to rising inequality, rich-country voters optimally elect a populist promising to end globalization. Countries with more inequality, higher financial development, and current account deficits are more vulnerable to populism, both in the model and in the data. Evidence on who voted for Brexit and Trump in 2016 also supports the model.

Math Science Lectures in Honor of Raoul Bott: Mina Aganagic
2019-04-09 16:00 - 17:00 | Harvard Science Center, 1 Oxford Street, Cambridge, MA, 02138
On April 9 and 10, 2019 the CMSA hosted two lectures by Mina Aganagic (UC Berkeley). This was the second annual Math Science Lecture Series held in honor of Raoul Bott.
The lectures took place in Science Center, Hall C
“Two math lessons from string theory”

April 9, 2019
Lecture 1
Title: “Lesson on Integrability”
Abstract: The quantum Knizhnik-Zamolodchikov (qKZ) equation is a difference generalization of the famous Knizhnik-Zamolodchikov (KZ) equation. The problem to explicitly capture the monodromy of the qKZ equation has been open for over 25 years. I will describe the solution to this problem, discovered jointly with Andrei Okounkov. The solution comes from the geometry of Nakajima quiver varieties and has a string theory origin.
Part of the interest in the qKZ monodromy problem is that its solution leads to integrable lattice models, in parallel to how monodromy matrices of the KZ equation lead to knot invariants. Thus, our solution of the problem leads to a new, geometric approach, to integrable lattice models. There are two other approaches to integrable lattice models, due to Nekrasov and Shatashvili and to Costello, Witten and Yamazaki. I’ll describe joint work with Nikita Nekrasov which explains how string theory unifies the three approaches to integrable lattice models.

April 10, 2019
Lecture 2
Title: “Lesson on Knot Categorification”
Abstract: An old problem is to find a unified approach to the knot categorification problem. The new string theory perspective on the qKZ equation I described in the first talk can be used to derive two geometric approaches to the problem.
The first approach is based on a category of B-type branes on resolutions of slices in affine Grassmannians. The second is based on a category of A-branes in a Landau-Ginzburg theory. The relation between them is two dimensional (equivariant) mirror symmetry. String theory also predicts that a third approach to categorification, based on counting solutions to five dimensional Haydys-Witten equations, is equivalent to the first two.
This talk is mostly based on joint work with Andrei Okounkov.

4/8/2019 Mathematical Physics Seminar
2019-04-08 12:00 - 13:00 | MA

4/4/2019 Random Matrix and Probability Theory Seminar
2019-04-04 16:30 - 17:30 | MA

4/4/2019 General Relativity Seminar
2019-04-04 15:30 - 16:30 | MA

4/3/2019 Fluid Dynamics Seminar
2019-04-03 20:54 | MA

Deregulation through Direct Democracy: Lessons from Liquor
2019-04-03 14:30 - 15:30 | CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Speaker: Sarah Moshary (University of Chicago)
Title: Deregulation through Direct Democracy: Lessons from Liquor
Abstract: This paper examines the merits of state control versus private provision of spirits retail, using the 2012 deregulation of liquor sales in Washington state as an event study. We document effects along a number of dimensions: prices, product variety, convenience, substitution to other goods, state revenue, and consumption externalities. We estimate a demand system to evaluate the net effect of privatization on consumer welfare. Our findings suggest that deregulation harmed the median Washingtonian, even though residents voted in favor of deregulation by a 16% margin. Further, we find that vote shares for the deregulation initiative do not reflect welfare gains at the ZIP code level. We discuss implications of our findings for the efficacy of direct democracy as a policy tool.

4/1/2019 Mathematical Physics Seminar
2019-04-01 12:00 - 13:00 | MA

4/1/2020 Quantum Matter seminar
2019-04-01 10:30 - 12:00 | MA

3/28/2019 Random Matrix and Probability Theory Seminar
2019-03-28 16:30 - 17:30 | MA

Hyperbolic geometry of the olfactory space
2019-03-27 17:15 - 18:15 | CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Speaker: Tatyana Sharpee (Salk Institute for Biological Studies)
Title: Hyperbolic geometry of the olfactory space
Abstract: The sense of smell can be used to avoid poisons or estimate a food’s nutrition content because biochemical reactions create many by-products. Thus, the presence of certain bacteria in the food becomes associated with the emission of certain volatile compounds. This perspective suggests that it would be convenient for the nervous system encode odors based on statistics of their co-occurrence within natural mixtures rather than based on the chemical structure per se. I will discuss how this statistical perspective makes it possible to map odors to points in a hyperbolic space. Hyperbolic coordinates have a long but often underappreciated history of relevance to biology. For example, these coordinates approximate distance between species computed along dendograms, and more generally between points within hierarchical tree-like networks. We find that these coordinates, which were generated purely based on the statistics of odors in the natural environment, provide a contiguous map of human odor pleasantness. Further, a separate analysis of human perceptual descriptions of smells indicates that these also generate a three dimensional hyperbolic representation of odors. This match in geometries between natural odor statistics and human perception can help to minimize distortions that would otherwise arise when mapping odors to perception. We identify three axes in the perceptual space that are aligned with odor pleasantness, its molecular boiling point and acidity. Because the perceptual space is curved, one can predict odor pleasantness by knowing the coordinates along the molecular boiling point and acidity axes.

Machine Learning for Multiscale Model Reduction Workshop
2019-03-27 09:00 - 2019-03-29 16:00 | Virtual
The Machine Learning for Multiscale Model Reduction Workshop will take place on March 27-29, 2019. This is the second of two workshops organized by Michael Brenner, Shmuel Rubinstein, and Tom Hou. The first, Fluid turbulence and Singularities of the Euler/ Navier Stokes equations, will take place on March 13-15, 2019. Both workshops will be held in room G10 of the CMSA, located at 20 Garden Street, Cambridge, MA.

Speakers:

Joan Bruna, Courant Institute
Predrag Cvitanovic, Georgia Tech
Stephan Hoyer, Google Research
De Huang, Caltech
George Karniadakis, Brown University
Richard Kerswell, Cambridge University
Stephane Mallat, ENS
Stanley Osher, UCLA
Jacob Page, Cambridge University
Houman Owhadi, Caltech
Zuowei Shen, National University of Singapore
Jack Xin, UC Irvine
Jinchao Xu, Penn State University
Lexing Ying, Stanford University and Facebook AI Research
Pengchuan Zhang, Microsoft Research

3/25/2019 Mathematical Physics Seminar
2019-03-25 12:00 - 13:00 | MA

Quality Externalities on Platforms: The Case of Airbnb
2019-03-20 16:30 - 17:30 | CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Speaker: Sonia Jaffe (Microsoft)
Title: Quality Externalities on Platforms: The Case of Airbnb
Abstract: We explore quality externalities on platforms: when buyers have limited information, a seller’s quality affects whether her buyers return to the platform, thereby impacting other sellers’ future business. We propose an intuitive measure of this externality, applicable across a range of platforms. Guest Return Propensity (GRP) is the aggregate propensity of a seller’s customers to return to the platform. We validate this metric using Airbnb data: matching customers to listings with a one standard deviation higher GRP causes them to take 17% more subsequent trips. By directing buyers to higher-GRP sellers, platforms may be able to increase overall seller surplus. (Joint work with Peter Coles, Steven Levitt, and Igor Popov.)

3/20/2019 Fluid Dynamics Seminar
2019-03-20 15:00 - 16:00 | MA

Workshop on Mirror Symmetry and Stability
2019-03-18 09:00 - 2019-03-20 17:00 | CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
This three-day workshop will take place at Harvard University on March 18-20, 2019 in Science Center room 507. The main topic will be stability conditions in homological mirror symmetry. This workshop is funded by the Simons Collaboration in Homological Mirror Symmetry.
Organizers: Denis Auroux, Yu-Wei Fan, Hansol Hong, Siu-Cheong Lau, Bong Lian, Shing-Tung Yau, Jingyu Zhao
Speakers:
Dylan Allegretti (Sheffield)
Tristan Collins (MIT)
Naoki Koseki (Tokyo)
Chunyi Li (Warwick)
Jason Lo (CSU Northridge)
Emanuele Macrì (NEU & IHES)
Genki Ouchi (Riken iTHEMS)
Pranav Pandit (ICTS)
Laura Pertusi (Edinburgh)
Jacopo Stoppa (SISSA)
Alex Takeda (UC Berkeley)
Xiaolei Zhao (UC Santa Barbara)
More details will be added later.
Visit the event page for more information.

3/14/2019 Random Matrix and Probability Theory Seminar
2019-03-14 17:45 | MA

3/14/2019 General Relativity Seminar
2019-03-14 15:30 - 16:30 | MA

On the geometry and topology of initial data sets in General Relativity
2019-03-13 17:15 - 18:15 | CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Speaker: Greg Galloway (University of Miami)
Title: On the geometry and topology of initial data sets in General Relativity
Abstract: A theme of long standing interest (to the speaker!) concerns the relationship between the topology of spacetime and the occurrence of singularities (causal geodesic incompleteness). Many results concerning this center around the notion of topological censorship, which has to do with the idea that the region outside all black holes (and white holes) should be simple. The aim of the results to be presented is to provide support for topological censorship at the pure initial data level, thereby circumventing difficult issues of global evolution. The proofs rely on the recently developed theory of marginally outer trapped surfaces, which are natural spacetime analogues of minimal surfaces in Riemannian geometry. The talk will begin with a brief overview of general relativity and topological censorship. The talk is based primarily on joint work with various collaborators: Lars Andersson, Mattias Dahl, Michael Eichmair and Dan Pollack.

3/13/2019 Special Seminar
2019-03-13 12:15 - 13:15 | MA

Fluid turbulence and Singularities of the Euler/ Navier Stokes equations
2019-03-13 09:00 - 2019-03-15 17:00 | CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
The Workshop on Fluid turbulence and Singularities of the Euler/ Navier Stokes equations will take place on March 13-15, 2019. This is the first of two workshop organized by Michael Brenner, Shmuel Rubinstein, and Tom Hou. The second, Machine Learning for Multiscale Model Reduction, will take place on March 27-29, 2019. Both workshops will be held in room G10 of the CMSA, located at 20 Garden Street, Cambridge, MA.

Speakers:

Claude Bardos, University of Paris
Jiajie Chen, Caltech
Peter Constantin, Princeton
Diego Cordoba, ICMAT
Tarek Elgindi, UCSD
Susumu Goto, Osaka
Alexander Kiselev, Duke University
Alain Pumir, ENS Lyon
Shmuel Rubinstein, Harvard SEAS
Vladimir Sverak, University of Minnesota
Edriss S. Titi, TAMU
Vlad Vicol, Courant
Sijue Wu, University of Michigan
Andrej Zlatos, UCSD

3/11/2019 Special Seminar
2019-03-11 16:15 | MA

3/11/2019 Social Science Applications Forum
2019-03-11 14:30 - 16:00 | MA

3/11/2019 Mathematical Physics Seminar
2019-03-11 12:00 - 13:00 | MA

3/8/2019 Special Seminar
2019-03-08 15:00 - 16:00 | MA

3/7/2019 Social Science Applications Forum
2019-03-07 14:30 - 15:00 | MA

3/6/2019 Random Matrix & Probability Theory Seminar
2019-03-06 16:15 - 17:15 | MA

3/6/2019 Fluid Dynamics Seminar
2019-03-06 15:00 - 16:00 | MA

3/4/2019 Mathematical Physics Seminar
2019-03-04 12:00 - 14:00 | MA

A sharp transition for Gibbs measures associated to the nonlinear Schrödinger equation
2019-02-28 14:30 - 15:00 | CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Speaker: Philippe Sosoe (Cornell)
Title: A sharp transition for Gibbs measures associated to the nonlinear Schrödinger equation
Abstract: In 1987, Lebowitz, Rose and Speer (LRS) showed how to construct formally invariant measures for the nonlinear Schrödinger equation on the torus. This seminal contribution spurred a large amount of activity in the area of partial differential equations with random initial data. In this talk, I will explain LRS’s result, and discuss a sharp transition in the construction of the Gibbs-type invariant measures considered by these authors. (Joint work with Tadahiro Oh and Leonardo Tolomeo)
