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Seminar information archive
Seminar information archive ～03/06｜Today's seminar 03/07 | Future seminars 03/08～
2020/02/13
Discrete mathematical modelling seminar
16:30-18:30 Room #126 (Graduate School of Math. Sci. Bldg.)
Sanjay Ramassamy (IPhT, CEA Saclay)
Embeddings adapted to two-dimensional models of statistical mechanics (English)
Sanjay Ramassamy (IPhT, CEA Saclay)
Embeddings adapted to two-dimensional models of statistical mechanics (English)
[ Abstract ]
A discrete model of statistical mechanics in 2D (for example simple random walk on the infinite square grid) can be defined on a graph without specifying a particular embedding of this graph. However, when stating that such a model converges to a conformally invariant object in the scaling limit, one needs to specify an embedding of the graph. For models which possess a local move, such as a star-triangle transformation, one would like the choice of the embedding to be compatible with that local move.
In this talk I will present a candidate for an embedding adapted to the 2D dimer model (a.k.a. random perfect matchings) on bipartite graphs, that is, graphs whose faces all have an even degree. This embedding is obtained by considering centers of circle patterns with the combinatorics of the graph on which the dimer model lives.
This is based on joint works with Dmitry Chelkak (École normale supérieure), Richard Kenyon (Yale University), Wai Yeung Lam (Université du Luxembourg) and Marianna Russkikh (MIT).
A discrete model of statistical mechanics in 2D (for example simple random walk on the infinite square grid) can be defined on a graph without specifying a particular embedding of this graph. However, when stating that such a model converges to a conformally invariant object in the scaling limit, one needs to specify an embedding of the graph. For models which possess a local move, such as a star-triangle transformation, one would like the choice of the embedding to be compatible with that local move.
In this talk I will present a candidate for an embedding adapted to the 2D dimer model (a.k.a. random perfect matchings) on bipartite graphs, that is, graphs whose faces all have an even degree. This embedding is obtained by considering centers of circle patterns with the combinatorics of the graph on which the dimer model lives.
This is based on joint works with Dmitry Chelkak (École normale supérieure), Richard Kenyon (Yale University), Wai Yeung Lam (Université du Luxembourg) and Marianna Russkikh (MIT).
2020/02/12
Seminar on Probability and Statistics
15:00-16:10 Room #126 (Graduate School of Math. Sci. Bldg.)
Lorenzo Mercuri (University of Milan)
Handling the underlying noise of Stochastic Differential Equations in YUIMA project
Lorenzo Mercuri (University of Milan)
Handling the underlying noise of Stochastic Differential Equations in YUIMA project
[ Abstract ]
Some advances in the implementation of advanced mathematical tools and numerical methods for an object of class yuima.law are presented and discussed. An object of yuima.law-class refers to the mathematical description of the underlying noise specified in the formal definition of a general Stochastic Differential Equation. Its aim is to create a link between YUIMA and other R packages available on CRAN for managing specific Lévy noises. Here we present as examples the simulation and the estimation of a CARMA(p,q) and Point Process regression models.
Some advances in the implementation of advanced mathematical tools and numerical methods for an object of class yuima.law are presented and discussed. An object of yuima.law-class refers to the mathematical description of the underlying noise specified in the formal definition of a general Stochastic Differential Equation. Its aim is to create a link between YUIMA and other R packages available on CRAN for managing specific Lévy noises. Here we present as examples the simulation and the estimation of a CARMA(p,q) and Point Process regression models.
2020/02/05
Lie Groups and Representation Theory
15:00-16:00 Room #126 (Graduate School of Math. Sci. Bldg.)
Simon Gindikin (Rutgers University)
Direct inversion of the horospherical transform on Riemannian symmetric spaces (English)
Simon Gindikin (Rutgers University)
Direct inversion of the horospherical transform on Riemannian symmetric spaces (English)
[ Abstract ]
It was a problem of Gelfand to find an inversion of the horospherical transform directly and as a result to find directly the Plancherel formula.
I will give such an inversion and it gives a formula different from Harish-Chandra's one.
It was a problem of Gelfand to find an inversion of the horospherical transform directly and as a result to find directly the Plancherel formula.
I will give such an inversion and it gives a formula different from Harish-Chandra's one.
2020/01/31
thesis presentations
9:15-10:30 Room #118 (Graduate School of Math. Sci. Bldg.)
thesis presentations
10:45-12:00 Room #118 (Graduate School of Math. Sci. Bldg.)
thesis presentations
12:45-14:00 Room #118 (Graduate School of Math. Sci. Bldg.)
thesis presentations
14:15-15:30 Room #118 (Graduate School of Math. Sci. Bldg.)
thesis presentations
9:15-10:30 Room #122 (Graduate School of Math. Sci. Bldg.)
thesis presentations
10:45-12:00 Room #122 (Graduate School of Math. Sci. Bldg.)
thesis presentations
12:45-14:00 Room #122 (Graduate School of Math. Sci. Bldg.)
thesis presentations
14:15-15:30 Room #122 (Graduate School of Math. Sci. Bldg.)
thesis presentations
9:15-10:30 Room #126 (Graduate School of Math. Sci. Bldg.)
thesis presentations
10:45-12:00 Room #126 (Graduate School of Math. Sci. Bldg.)
thesis presentations
12:45-14:00 Room #126 (Graduate School of Math. Sci. Bldg.)
thesis presentations
14:15-15:30 Room #126 (Graduate School of Math. Sci. Bldg.)
2020/01/30
thesis presentations
10:45-12:00 Room #118 (Graduate School of Math. Sci. Bldg.)
thesis presentations
12:45-14:00 Room #118 (Graduate School of Math. Sci. Bldg.)
thesis presentations
14:15-15:30 Room #118 (Graduate School of Math. Sci. Bldg.)
thesis presentations
15:45-17:00 Room #118 (Graduate School of Math. Sci. Bldg.)
thesis presentations
9:15-10:30 Room #122 (Graduate School of Math. Sci. Bldg.)
thesis presentations
12:45-14:00 Room #122 (Graduate School of Math. Sci. Bldg.)
thesis presentations
13:45-15:00 Room #126 (Graduate School of Math. Sci. Bldg.)
2020/01/29
Operator Algebra Seminars
13:00-14:30 Room #002 (Graduate School of Math. Sci. Bldg.)
Colin McSwiggen (Brown Univ.)
Horn's problem, polytope volumes and tensor product decompositions (English)
Colin McSwiggen (Brown Univ.)
Horn's problem, polytope volumes and tensor product decompositions (English)
Operator Algebra Seminars
16:45-18:15 Room #126 (Graduate School of Math. Sci. Bldg.)
Cyril Houdayer (Univ. Paris-Sud)
Stationary actions of higher rank lattices on von Neumann algebras (English)
Cyril Houdayer (Univ. Paris-Sud)
Stationary actions of higher rank lattices on von Neumann algebras (English)
2020/01/28
Tuesday Seminar on Topology
17:00-18:00 Room #056 (Graduate School of Math. Sci. Bldg.)
Nozomu Sekino (The University of Tokyo)
Existence problems for fibered links (JAPANESE)
Nozomu Sekino (The University of Tokyo)
Existence problems for fibered links (JAPANESE)
[ Abstract ]
It is known that every connected orientable closed 3-manifold has a fibered knot. However, finding (and classifying) fibered links whose fiber surfaces are fixed homeomorphism type in a given 3-manifold is difficult in general. We give a criterion of a simple closed curve on a genus 2g Heegaard surface being a genus g fibered knot in terms of its Heegaard diagram. As an application, we can prove the non-existence of genus one fibered knots in some Seifert manifolds.
There is one generalization of fibered links, homologically fibered links. This requests that the complement of the "fiber surface" is a homologically product of a surface and an interval. We give a necessary and sufficient condition for a connected sums of lens spaces of having a homologically fibered link whose fiber surfaces are some fixed types as some algebraic equations.
It is known that every connected orientable closed 3-manifold has a fibered knot. However, finding (and classifying) fibered links whose fiber surfaces are fixed homeomorphism type in a given 3-manifold is difficult in general. We give a criterion of a simple closed curve on a genus 2g Heegaard surface being a genus g fibered knot in terms of its Heegaard diagram. As an application, we can prove the non-existence of genus one fibered knots in some Seifert manifolds.
There is one generalization of fibered links, homologically fibered links. This requests that the complement of the "fiber surface" is a homologically product of a surface and an interval. We give a necessary and sufficient condition for a connected sums of lens spaces of having a homologically fibered link whose fiber surfaces are some fixed types as some algebraic equations.
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