Monday, February 19
Presidents' Day (regional holiday)
When:        Mon, Feb 19
Public holiday in: Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, District of Columbia, Florida, Hawaii, Idaho, Illinois, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New York, North Dakota, Northern Mariana Islands, Ohio, Oklahoma, Oregon, Pennsylvania, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wyoming

1:00pm    Grad / Postdoc Professional Development Seminar: No seminar - No seminar
Where:      Math Tower P-131When:        Mon, Feb 19    1:00pm — 2:30pm
Title:          No seminar

Abstract:    No seminar due to President Stanley's visit.
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2:00pm    SCGP: Weekly Physics Meetings: Connor Behan
Where:      SCGP 313When:        Mon, Feb 19    2:00pm — 3:00pm
Title:          CFT data on conformal manifolds
Tuesday, February 20
1:00pm    SCGP: SCGP Weekly Talk - Marek Karliner
When:        Tue, Feb 20    1:00pm — 2:00pm
Title:          The Social Life of Heavy Quarks
Wednesday, February 21
11:30am    RTG Seminar: Yoonjoo Kim - The Hilbert-Mumford Criterion for Stability
Where:      5-127When:        Wed, Feb 21    11:30am — 12:30pm
Title:          The Hilbert-Mumford Criterion for Stability
Speaker:   Yoonjoo Kim [Stony Brook University]

Abstract:    In this talk we will focus our attention on the notion of stability previously introduced for these actions by reductive groups. We will state a theorem, due in part to Hilbert and Mumford respectively, which detects the (semi)stable points of an action using an eigenanalysis of the 1-parameter subgroups, complete with examples.
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1:00pm    Graduate Student Seminar: Prithviraj Chowdhury - TBA
Where:      Math Tower P-131When:        Wed, Feb 21    1:00pm — 2:00pm
Title:          TBA
Speaker:   Prithviraj Chowdhury [Stony Brook University]

Abstract:    TBA
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1:30pm    SCGP: Physics Seminar: Austin Joyce
Where:      SCGP 313When:        Wed, Feb 21    1:30pm — 2:30pm
Title:          Spin-2 scattering amplitudes and asymptotic superluminality

2:30pm    Mini Course / Dynamics Learning Seminar: Babak Modami - Minimal nonuniquely ergodic foliations on surfaces: I
Where:      Math Tower P-131When:        Wed, Feb 21    2:30pm — 3:30pm
Title:          Minimal nonuniquely ergodic foliations on surfaces: I
Speaker:   Babak Modami [Stony Brook University]

Abstract:    Measured foliations (laminations) on surfaces are well-known examples of dynamical systems in low dimension. The first return maps of measured foliations are interval exchange transformations which have been studied extensively. Measured foliations also determine the trajectories of Teichm\"uller and Weil-Petersson geodesics in the Teichm\"uller space.

In this mini-course, I outline my joint work with Brock, Leininger and Rafi about construction of minimal nonuniquely ergodic laminations.
This work was inspired by a construction of Gabai and the earlier work of Lenzhen-Leininger-Rafi where laminations are realized as the limits of sequences of curves on surfaces. An advantage of our method is explicit estimates for intersection numbers of the curves in sequences and the associated subsurface coefficients. These estimates are crucial to control the behavior of geodesics and determine their limit sets in the Thurston compactification of Teichm\"uller space (which won't be discussed in the minicourse).
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4:00pm    Algebraic geometry seminar: Jian Xiao - Local positivity for curves
Where:      Math Tower P-131When:        Wed, Feb 21    4:00pm — 5:30pm
Title:          Local positivity for curves
Speaker:   Jian Xiao [Northwestern]

Abstract:    One of the most important invariants measuring the local positivity of a nef line bundle is the local Seshadri function introduced by Demailly. We first give a brief introduction to this invariant. Then using the duality of positive cones, we show that applying the polar transform from convex analysis to local positivity invariants for divisors gives interesting and new local positivity invariants for curves. These new invariants, studied also independently by M. Fulger, have nice properties similar to those for divisors. In particular, this enables us to obtain a Seshadri type ampleness criterion for movable curves, and give a characterization of the divisorial components of the non-ample locus of a big class. (Joint work with N. McCleerey.)

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Thursday, February 22
1:00pm    Symplectic Geometry Seminar: Yuhan Sun - Finding nondisplaceable Lagrangian tori via toric degeneration.
Where:      Math Tower 5-127When:        Thu, Feb 22    1:00pm — 2:00pm
Title:          Finding nondisplaceable Lagrangian tori via toric degeneration.
Speaker:   Yuhan Sun [Stony Brook University]

Abstract:    Starting with a semi-Fano toric surface, I will explain how to find families of Lagrangian tori with nontrivial deformed Floer cohomology. The proof uses toric degeneration method to compute the potential functions of these tori.
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2:30pm    YITP: Pheno seminar: Prateek Agrawal (Harvard). "The strong CP problem and UV instantons"
When:        Thu, Feb 22    2:30pm — 3:30pm
The absence of sizeable CP violation in the strong sector is a long standing puzzle. A class of solutions to this problem rely on a global U(1) symmetry that is anomalous with QCD. These solutions lead to robust low-energy predictions, for example a massless up quark or a light axion. I will present simple extensions to such solutions which can dramatically change these low-energy predictions. In our models, contributions from small instantons play a significant role in affecting the low-energy physics while preserving the solution to the strong CP problem.

4:00pm    Colloquium: Nets Katz - Semialgebraic sets and the Kakeya Problem
Where:      Math Tower P-131When:        Thu, Feb 22    4:00pm — 5:00pm
Title:          Semialgebraic sets and the Kakeya Problem
Speaker:   Nets Katz [Caltech]

Abstract:    In joint work with Keith Rogers, we study the connection between the Kakeya problem and the highlights of the theory of semialgebraic sets such as Tarski's projection theorem and Gromov's algebraic lemma.
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Friday, February 23
2:30pm    Student Algebraic Geometry Seminar: Sasha Victorova - Canonical models, minimal models and their singularities
Where:      Math Tower 5-127When:        Fri, Feb 23    2:30pm — 3:30pm
Title:          Canonical models, minimal models and their singularities
Speaker:   Sasha Victorova [Stony Brook University]

Abstract:    In this talk we will run with the definitions of canonical and terminal singularities from last week and use them to give definitions of canonical and minimal models of (quasi-)projective varieties. As usual we will turn to examples to motivate the main ideas.
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2:30pm    Dynamical Systems Seminar: Zhiqiang Li - Prime orbit theorems for expanding Thurston maps
Where:      Math Tower P-131When:        Fri, Feb 23    2:30pm — 3:30pm
Title:          Prime orbit theorems for expanding Thurston maps
Speaker:   Zhiqiang Li [Stony Brook University]

Abstract:    Analogues of the Riemann zeta function were first introduced into geometry by A. Selberg and into dynamics by M. Artin, B. Mazur, and S. Smale. Analytic studies of such dynamical zeta functions yield quantitative information on the distribution of closed geodesics and periodic orbits.

We obtain the first Prime Orbit Theorem, as an analogue of the Prime Number Theorem, in complex dynamics outside of hyperbolic maps, for a class of branched covering maps on the $2$-sphere called expanding Thurston maps $f$. More precisely, we show that the number of primitive periodic orbits of $f$, ordered by a weight on each point induced by a non-constant real-valued H\"{o}lder continuous function on $S^2$ satisfying some additional regularity conditions, is asymptotically the same as the well-known logarithmic integral, with an exponentially small error term. Such a result follows from our quantitative study of the holomorphic extension properties of the associated dynamical zeta functions and dynamical Dirichlet series.

In particular, the above result applies to postcritically-finite rational maps whose Julia set is the whole Riemann sphere. Moreover, we prove that the regularity conditions needed here are generic; and for a Latt\`{e}s map $f$, a continuously differentiable function satisfies such a condition if and only if it is not cohomologous to a constant. This is a joint work with T. Zheng.
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Monday, February 26
1:00pm    Grad / Postdoc Professional Development Seminar: Robert Lazarsfeld - Robert's rules of publishing
Where:      Math Tower P-131When:        Mon, Feb 26    1:00pm — 2:30pm
Title:          Robert's rules of publishing
Speaker:   Robert Lazarsfeld [Stony Brook University]

Abstract:
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2:00pm    SCGP: Weekly Physics Meetings: Zohar Komargodski
When:        Mon, Feb 26    2:00pm — 3:00pm
Tuesday, February 27
5:30pm    First and Second Year Student Seminar: David Ebin - TBA
Where:      Math Tower 5-127When:        Tue, Feb 27    5:30pm — 6:30pm
Title:          TBA
Speaker:   David Ebin [Stony Brook University]

Abstract:
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