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Upcoming Colloquia & Seminars

  1. HDMP-Lunch Q&A session

    Location: MSRI: Commons Room
    Created on Oct 04, 2019 10:50 AM PDT
  2. HDMP - Weekly Seminar (Part 1): Ideal webs on surfaces and character varieties

    Location: MSRI: Simons Auditorium
    Speakers: Alexander Goncharov (Yale University)

    I will introduce ideal webs = ideal bipartite graphs on decorated surfaces. They are the simplest possible higher rank analogs of ideal triangulations of decorated surfaces.  

    I will explain how to use them to define cluster atlases on several flavors of character varieties for the groups of type A_m, equivariant under the action of the mapping class group, and how to define a related family of 3d Calabi-Yau categories, also equivariant under the action of the mapping class group.

    It is an expository talk, mostly following arXiv:1607.05228

     

    Updated on Oct 17, 2019 08:52 AM PDT
  3. HDMP-Weekly Seminar (Part 2): Ideal webs on surfaces and character varieties

    Location: MSRI: Simons Auditorium
    Speakers: Alexander Goncharov (Yale University)

    I will introduce ideal webs = ideal bipartite graphs on decorated surfaces. They are the simplest possible higher rank analogs of ideal triangulations of decorated surfaces.  

    I will explain how to use them to define cluster atlases on several flavors of character varieties for the groups of type A_m, equivariant under the action of the mapping class group, and how to define a related family of 3d Calabi-Yau categories, also equivariant under the action of the mapping class group.

    It is an expository talk, mostly following arXiv:1607.05228

    Updated on Oct 17, 2019 08:52 AM PDT
  4. MLA - Weekly Seminar (Part 1): Microlocal analysis in SAR inverse problems

    Location: MSRI: Simons Auditorium
    Speakers: Raluca Felea (Rochester Institute of Technology)

    We will use the microlocal analysis to describe and compare the monostatic Synthetic aperture radar (SAR) imaging and the  Doppler SAR imaging.   In these problems, the forward operator F, which maps the image to the data is a  FIO with singularities: folds, cusps, blowdowns. We will focus on the composition calculus of these operators and we will  consider the normal operator F*F.  This method produces artifacts  which can be classified as smooth Lagrangians like canonical graphs or two-sided folds or as singular Lagrangians like open umbrellas.

    Updated on Oct 18, 2019 09:23 AM PDT
  5. MLA - Weekly Seminar (Part 2): Sharp stability estimate for tensor tomography in non-positive curvature

    Location: MSRI: Simons Auditorium
    Speakers: Gabriel Paternain (Center for Mathematical Sciences)

    I will discuss a stability estimate for the geodesic X-ray transform acting on solenoidal tensor fields on a compact simply connected manifold with strictly convex boundary and non-positive curvature.

    The estimate is of the form $L^2\mapsto H^{1/2}_{T}$, where the $H^{1/2}_{T}$-space is defined using the natural parametrization of geodesics as initial boundary points and incoming directions (fan-beam geometry). Only tangential derivatives at the boundary are used. The proof is based on the observation that the Pestov identity with boundary term localizes in frequency. This estimate answers a question raised by Boman and Sharafutdinov.

    Updated on Oct 18, 2019 09:27 AM PDT
  6. MLA - Regular Seminar (part 1): Linear and nonlinear theory in graphs

    Location: MSRI: Simons Auditorium
    Speakers: Jeremy Marzuola (University of North Carolina)

    I will discuss a collection of recent results on both linear and nonlinear results on discrete and quantum graphs. First I will discuss results related to spectral theory for the (possibly magnetic) Laplacian on a variety of graphs that relates to work with Berkolaiko, Canzani, Cox, Weinstein and others. I will also discuss nonlinear equations on graphs that comprises work with Bandres, Berkolaiko, Osting, Pelinovsky, Rechtsman,  and others. 

    Updated on Oct 18, 2019 01:57 PM PDT
  7. MLA - Regular Seminar (Part 2): Determining a Lorentzian metric from the source-to-solution map for the relativistic Boltzmann equation

    Location: MSRI: Simons Auditorium
    Speakers: Tracey Balehowsky (University of Helsinki)

    In this talk, we consider the following question: Given the source to solution map for a relativistic Boltzmann equation on a known open set $V$ of a Lorentzian spacetime $(\mathbb{R}\times N,g)$, can we use this data to uniquely determine the spacetime metric on an unknown region of $\mathbb{R}\times N$?

    We will show that the answer is yes. Precisely, we determine the metric on the domain of causal influence for the set $V$. Key to our proof is that the nonlinear term in the relativistic Boltzmann equation which describes the behaviour of particle collisions captures information about a source-to-solution map for a related linearized problem. We use this relationship together with an analysis of the behaviour of particle collisions by classical microlocal techniques to determine the set of locations in $V$ where we first receive light signals from collisions in the unknown domain. From this data we are able to parametrize the unknown region and determine the metric.

    The technique of using the nonlinearity in a partial differential equation as a feature with which to gain knowledge of a related linearized problem first appeared in [1] in the context of a wave equation with a quadratic nonlinearity. We will briefly survey this and related work as they provide context for our result. 

    The new results presented in this talk is joint work with Antti Kujanapää, Matti Lassas, and Tony Liimatainen (University of Helsinki).

    [1] Kuylev Y., Lassas M., Uhlmann G., Inventiones mathematicae 212.3 (2018): 781-857.

    Updated on Oct 18, 2019 01:57 PM PDT
  8. MLA-Graduate Student Seminar

    Location: MSRI: Simons Auditorium
    Created on Aug 26, 2019 02:41 PM PDT
  9. HDMP-Lunch Q&A session

    Location: MSRI: Commons Room
    Created on Oct 04, 2019 10:50 AM PDT
  10. HDMP - Weekly Seminar (Part 1)

    Location: MSRI: Simons Auditorium
    Updated on Sep 26, 2019 01:31 PM PDT
  11. HDMP-Weekly Seminar (Part 2)

    Location: MSRI: Simons Auditorium
    Updated on Sep 26, 2019 01:49 PM PDT
  12. MLA - Weekly Seminar (Part 1)

    Location: MSRI: Simons Auditorium
    Created on Aug 27, 2019 01:13 PM PDT
  13. MLA - Weekly Seminar (Part 2)

    Location: MSRI: Simons Auditorium
    Created on Aug 27, 2019 01:18 PM PDT
  14. MLA-Graduate Student Seminar

    Location: MSRI: Simons Auditorium
    Created on Aug 26, 2019 02:41 PM PDT
  15. HDMP-Lunch Q&A session

    Location: MSRI: Commons Room
    Created on Oct 04, 2019 10:50 AM PDT
  16. HDMP - Weekly Seminar (Part 1)

    Location: MSRI: Simons Auditorium
    Updated on Sep 26, 2019 01:31 PM PDT
  17. HDMP-Weekly Seminar (Part 2)

    Location: MSRI: Simons Auditorium
    Updated on Sep 26, 2019 01:50 PM PDT
  18. MLA - Weekly Seminar (Part 1)

    Location: MSRI: Simons Auditorium
    Created on Aug 27, 2019 01:13 PM PDT
  19. MLA - Weekly Seminar (Part 2)

    Location: MSRI: Simons Auditorium
    Created on Aug 27, 2019 01:18 PM PDT
  20. MLA-Graduate Student Seminar

    Location: MSRI: Simons Auditorium
    Created on Aug 26, 2019 02:41 PM PDT
  21. HDMP-Lunch Q&A session

    Location: MSRI: Commons Room
    Created on Oct 04, 2019 10:50 AM PDT
  22. HDMP - Weekly Seminar (Part 1)

    Location: MSRI: Simons Auditorium
    Updated on Sep 26, 2019 01:32 PM PDT
  23. HDMP-Weekly Seminar (Part 2)

    Location: MSRI: Simons Auditorium
    Updated on Sep 26, 2019 01:50 PM PDT
  24. MLA - Weekly Seminar (Part 1)

    Location: MSRI: Simons Auditorium
    Created on Aug 27, 2019 01:13 PM PDT
  25. MLA - Weekly Seminar (Part 2)

    Location: MSRI: Simons Auditorium
    Created on Aug 27, 2019 01:18 PM PDT
  26. MLA-Graduate Student Seminar

    Location: MSRI: Simons Auditorium
    Created on Aug 26, 2019 02:41 PM PDT
  27. HDMP-Lunch Q&A session

    Location: MSRI: Commons Room
    Created on Oct 04, 2019 10:50 AM PDT
  28. HDMP - Weekly Seminar (Part 1)

    Location: MSRI: Simons Auditorium
    Updated on Sep 26, 2019 01:32 PM PDT
  29. HDMP-Weekly Seminar (Part 2)

    Location: MSRI: Simons Auditorium
    Updated on Sep 26, 2019 01:51 PM PDT
  30. MLA - Weekly Seminar (Part 1)

    Location: MSRI: Simons Auditorium
    Created on Aug 27, 2019 01:13 PM PDT
  31. MLA - Weekly Seminar (Part 2)

    Location: MSRI: Simons Auditorium
    Created on Aug 27, 2019 01:18 PM PDT
  32. MLA-Graduate Student Seminar

    Location: MSRI: Simons Auditorium
    Created on Aug 26, 2019 02:41 PM PDT
  33. HDMP-Lunch Q&A session

    Location: MSRI: Commons Room
    Created on Oct 04, 2019 10:50 AM PDT
  34. HDMP - Weekly Seminar (Part 1)

    Location: MSRI: Simons Auditorium
    Updated on Sep 26, 2019 01:33 PM PDT
  35. HDMP-Weekly Seminar (Part 2)

    Location: MSRI: Simons Auditorium
    Updated on Sep 26, 2019 01:51 PM PDT
  36. MLA - Weekly Seminar (Part 1)

    Location: MSRI: Simons Auditorium
    Created on Aug 27, 2019 01:13 PM PDT
  37. MLA - Weekly Seminar (Part 2)

    Location: MSRI: Simons Auditorium
    Created on Aug 27, 2019 01:18 PM PDT
  38. MLA-Graduate Student Seminar

    Location: MSRI: Baker Board Room
    Created on Aug 26, 2019 02:41 PM PDT
  39. HDMP-Lunch Q&A session

    Location: MSRI: Commons Room
    Created on Oct 04, 2019 10:50 AM PDT
  40. HDMP - Weekly Seminar (Part 1)

    Location: MSRI: Simons Auditorium
    Updated on Sep 26, 2019 01:34 PM PDT
  41. HDMP-Weekly Seminar (Part 2)

    Location: MSRI: Simons Auditorium
    Updated on Sep 26, 2019 01:52 PM PDT
  42. MLA - Weekly Seminar (Part 1)

    Location: MSRI: Simons Auditorium
    Created on Aug 27, 2019 01:13 PM PDT
  43. MLA - Weekly Seminar (Part 2)

    Location: MSRI: Simons Auditorium
    Created on Aug 27, 2019 01:18 PM PDT