2/11/2019 Mathematical Physics Seminar
2019-02-11 12:00 - 14:00 (America/New_York) | MA

2/13/2019 Hodge and Noether-Lefschetz Loci Seminar
2019-02-13 13:30 - 15:00 | MA

2/13/2019 Special Algebraic Geometry Seminar
2019-02-13 15:00 - 16:00 | MA

2/14/2019 General Relativity Seminar
2019-02-14 15:00 - 16:00 | MA

2/14/2019 Random Matrix and Probability Theory Seminar
2019-02-14 16:30 - 17:30 | MA

2/20/2019 Fluid Dynamics Seminar
2019-02-20 15:00 - 16:00 | MA

Optimally Imprecise Memory and Biased Forecasts
2019-02-20 16:30 - 17:30 | CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Speaker: Michael Woodford (Columbia)
Title: Optimally Imprecise Memory and Biased Forecasts
Abstract: We propose a model of optimal decision making subject to a memory constraint. The constraint is a limit on the complexity of memory measured using Shannon’s mutual information, as in models of rational inattention; the structure of the imprecise memory is optimized (for a given decision problem and noisy environment) subject to this constraint. We characterize the form of the optimally imprecise memory, and show that the model implies that both forecasts and actions will exhibit idiosyncratic random variation; that beliefs will fluctuate forever around the rational-expectations (perfect-memory) beliefs with a variance that does not fall to zero; and that more recent news will be given disproportionate weight. The model provides a simple explanation for a number of features of observed forecast bias in laboratory and field settings. [Joint work with Rava Azeredo da Silveira and Yeji Sung

2/21/2019 Random Matrix and Probability Theory Seminar
2019-02-21 16:30 - 17:30 | MA

2/22/2019 Social Science Applications Forum
2019-02-22 14:00 | MA

Growth and zero sets of eigenfunctions and of solutions to elliptic partial differential equations
2019-02-25 09:30 - 2019-03-01 17:00 | CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
From February 25 to March 1, the CMSA will be hosting a workshop on Growth and zero sets of eigenfunctions and of solutions to elliptic partial differential equations.
Key participants of this workshop include David Jerison (MIT), Alexander Logunov (IAS), and Eugenia Malinnikova (IAS). This workshop will have morning sessions on Monday-Friday of this week from 9:30-11:30am, and afternoon sessions on Monday, Tuesday, and Thursday from 3:00-5:00pm.
The sessions will be held in (G02) (downstairs) at 20 Garden, except for Tuesday afternoon, when the talk will be in (G10).

2/25/2019 Math Physics Seminar
2019-02-25 12:00 - 14:00 | MA

02/26/2020 Random Matrix and Probability Theory Seminar
2019-02-26 14:00 - 15:00 | MA

Sentiment and Speculation in a Market with Heterogeneous Beliefs
2019-02-27 14:30 - 15:30 | CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Speaker: Ian Martin (LSE)
Title: Sentiment and Speculation in a Market with Heterogeneous Beliefs
Abstract: We present a dynamic model featuring risk-averse investors with heterogeneous beliefs. Individual investors have stable beliefs and risk aversion, but agents who were correct in hindsight become relatively wealthy; their beliefs are overrepresented in market sentiment, so “the market” is bullish following good news and bearish following bad news. Extreme states are far more important than in a homogeneous economy. Investors understand that sentiment drives volatility up, and demand high risk premia in compensation. Moderate investors supply liquidity: they trade against market sentiment in the hope of capturing a variance risk premium created by the presence of extremists. [Joint work with Dimitris Papadimitriou]

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)

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

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

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

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

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

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

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

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

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

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

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

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