Seminar information archive
Seminar information archive ～01/25｜Today's seminar 01/26  Future seminars 01/27～
2022/01/25
Tuesday Seminar on Topology
17:0018:00 Online
Preregistration required. See our seminar webpage.
Xiaobing Sheng (The Univesity of Tokyo)
Some obstructions on subgroups of the BrinThompson group $2V$ (ENGLISH)
https://park.itc.utokyo.ac.jp/MSF/topology/TuesdaySeminar/index_e.html
Preregistration required. See our seminar webpage.
Xiaobing Sheng (The Univesity of Tokyo)
Some obstructions on subgroups of the BrinThompson group $2V$ (ENGLISH)
[ Abstract ]
Motivated by Burillo, Cleary and Röver's summary of the obstruction for subgroups of Thompson's group $V$, we investigate the higher dimensional version, the group $2V$ and found out that they have similar obstructions on torsion subgroups and certain BaumslagSolitar groups.
[ Reference URL ]Motivated by Burillo, Cleary and Röver's summary of the obstruction for subgroups of Thompson's group $V$, we investigate the higher dimensional version, the group $2V$ and found out that they have similar obstructions on torsion subgroups and certain BaumslagSolitar groups.
https://park.itc.utokyo.ac.jp/MSF/topology/TuesdaySeminar/index_e.html
2022/01/24
Seminar on Geometric Complex Analysis
10:3012:00 Room #128 (Graduate School of Math. Sci. Bldg.)
Junjiro Noguchi (The University of Tokyo)
Analytic AxSchanuel Theorem for semiabelian varieties and Nevanlinna theory (Japanese)
https://utokyoacjp.zoom.us/meeting/register/tJ0vcu2rrDIqG9Rv5AT0Mpi37urIkJ1IRldB
Junjiro Noguchi (The University of Tokyo)
Analytic AxSchanuel Theorem for semiabelian varieties and Nevanlinna theory (Japanese)
[ Abstract ]
The present study is motivated by $\textit{Schanuel Conjecture}$, which in particular implies the algebraic independence of $e$ and $\pi$. Our aim is to explore, as a transcendental functional analogue of Schanuel Conjecture, the value distribution theory (Nevanlinna theory) of the entire curve $\widehat{\mathrm{ex}}_A f:=(\exp_Af,f):\mathbf{C} \to A \times \mathrm{Lie}(A)$ associated with an entire curve $f: \mathbf{C} \to \mathrm{Lie}(A)$, where $\exp_A:\mathrm{Lie}(A)\to A$ is an exponential map of a semiabelian variety $A$.
We firstly give a Nevanlinna theoretic proof to the $\textit{analytic AxSchanuel Theorem}$ for semiabelian varieties, which was proved by J. Ax 1972 in the case of formal power series $\mathbf{C}[[t]]$ (AxSchanuel Theorem). We assume some nondegeneracy condition for $f$ such that in the case of $A=(\mathbf{C}^*)^n$ and $\mathrm{Lie}((\mathbf{C}^*)^n)=\mathbf{C}^n$, the elements of the vectorvalued function $f(z)f(0)$ are $\mathbf{Q}$linearly independent. Then by the method of Nevanlinna theory (the Log BlochOchiai Theorem), we prove that $\mathrm{tr.deg}_\mathbf{C}\, \widehat{\mathrm{ex}}_A f \geq n+ 1.$
Secondly, we prove a $\textit{Second Main Theorem}$ for $\widehat{\mathrm{ex}}_A f$ and an algebraic divisor $D$ on $A \times \mathrm{Lie}(A)$ with compactifications $\bar D \subset \bar A \times \overline{\mathrm{Lie}(A)}$ such that
\[
T_{\widehat{\mathrm{ex}}_Af}(r, L({\bar D})) \leq N_1 (r,
(\widehat{\mathrm{ex}}_A f)^* D)+
\varepsilon T_{\exp_Af}(r)+O(\log r) ~~ _\varepsilon.
\]
We will also deal with the intersections of $\widehat{\mathrm{ex}}_Af$ with higher codimensional algebraic cycles of $A \times \mathrm{Lie}(A)$ as well as the case of higher jets.
[ Reference URL ]The present study is motivated by $\textit{Schanuel Conjecture}$, which in particular implies the algebraic independence of $e$ and $\pi$. Our aim is to explore, as a transcendental functional analogue of Schanuel Conjecture, the value distribution theory (Nevanlinna theory) of the entire curve $\widehat{\mathrm{ex}}_A f:=(\exp_Af,f):\mathbf{C} \to A \times \mathrm{Lie}(A)$ associated with an entire curve $f: \mathbf{C} \to \mathrm{Lie}(A)$, where $\exp_A:\mathrm{Lie}(A)\to A$ is an exponential map of a semiabelian variety $A$.
We firstly give a Nevanlinna theoretic proof to the $\textit{analytic AxSchanuel Theorem}$ for semiabelian varieties, which was proved by J. Ax 1972 in the case of formal power series $\mathbf{C}[[t]]$ (AxSchanuel Theorem). We assume some nondegeneracy condition for $f$ such that in the case of $A=(\mathbf{C}^*)^n$ and $\mathrm{Lie}((\mathbf{C}^*)^n)=\mathbf{C}^n$, the elements of the vectorvalued function $f(z)f(0)$ are $\mathbf{Q}$linearly independent. Then by the method of Nevanlinna theory (the Log BlochOchiai Theorem), we prove that $\mathrm{tr.deg}_\mathbf{C}\, \widehat{\mathrm{ex}}_A f \geq n+ 1.$
Secondly, we prove a $\textit{Second Main Theorem}$ for $\widehat{\mathrm{ex}}_A f$ and an algebraic divisor $D$ on $A \times \mathrm{Lie}(A)$ with compactifications $\bar D \subset \bar A \times \overline{\mathrm{Lie}(A)}$ such that
\[
T_{\widehat{\mathrm{ex}}_Af}(r, L({\bar D})) \leq N_1 (r,
(\widehat{\mathrm{ex}}_A f)^* D)+
\varepsilon T_{\exp_Af}(r)+O(\log r) ~~ _\varepsilon.
\]
We will also deal with the intersections of $\widehat{\mathrm{ex}}_Af$ with higher codimensional algebraic cycles of $A \times \mathrm{Lie}(A)$ as well as the case of higher jets.
https://utokyoacjp.zoom.us/meeting/register/tJ0vcu2rrDIqG9Rv5AT0Mpi37urIkJ1IRldB
2022/01/21
Colloquium
15:3016:30 Online
Registration is closed (12:00, January 21).
Yoshiko Ogata (Graduate School of Mathematical Sciences, The University of Tokyo)
Classification of gapped ground state phases in quantum spin systems (JAPANESE)
Registration is closed (12:00, January 21).
Yoshiko Ogata (Graduate School of Mathematical Sciences, The University of Tokyo)
Classification of gapped ground state phases in quantum spin systems (JAPANESE)
TokyoNagoya Algebra Seminar
16:4518:15 Online
Please see the URL below for details on the online seminar.
Haruhisa Enomoto (Osaka Prefecture University)
Exactcategorical properties of subcategories of abelian categories 2 (Japanese)
http://www.math.nagoyau.ac.jp/~aaron.chan/TNAseminar.html
Please see the URL below for details on the online seminar.
Haruhisa Enomoto (Osaka Prefecture University)
Exactcategorical properties of subcategories of abelian categories 2 (Japanese)
[ Abstract ]
Quillen's exact category is a powerful framework for studying extensionclosed subcategories of abelian categories, and provides many interesting questions on such subcategories.
In the first talk, I will explain the basics of some properties and invariants of exact categories (e.g. the JordanHolder property, simple objects, and Grothendieck monoid).
In the second talk, I will give some results and questions about particular classes of exact categories arising in the representation theory of algebras (e.g. torsion(free) classes over path algebras and preprojective algebras).
If time permits, I will discuss questions of whether these results can be generalized to extriangulated categories (extensionclosed subcategories of triangulated categories).
[ Reference URL ]Quillen's exact category is a powerful framework for studying extensionclosed subcategories of abelian categories, and provides many interesting questions on such subcategories.
In the first talk, I will explain the basics of some properties and invariants of exact categories (e.g. the JordanHolder property, simple objects, and Grothendieck monoid).
In the second talk, I will give some results and questions about particular classes of exact categories arising in the representation theory of algebras (e.g. torsion(free) classes over path algebras and preprojective algebras).
If time permits, I will discuss questions of whether these results can be generalized to extriangulated categories (extensionclosed subcategories of triangulated categories).
http://www.math.nagoyau.ac.jp/~aaron.chan/TNAseminar.html
2022/01/20
Seminar on Probability and Statistics
15:0016:10 Room # (Graduate School of Math. Sci. Bldg.)
Yoshimasa Uematsu ()

[ Reference URL ]
https://docs.google.com/forms/d/e/1FAIpQLSdH8oP72k7qsHigZBBZ4F6NbGIJ6BcOWgKLhted2ohGSBeg/viewform
Yoshimasa Uematsu ()

[ Reference URL ]
https://docs.google.com/forms/d/e/1FAIpQLSdH8oP72k7qsHigZBBZ4F6NbGIJ6BcOWgKLhted2ohGSBeg/viewform
2022/01/19
Mathematical Biology Seminar
15:0016:00 Online
Tsuyoshi Kajiwara (Professor Emeritus, Okayama University)
Destabilization induced by time delay, immunity and absorbing effect
(Japanese)
[ Reference URL ]
オンラインですので，参加希望のかたは稲葉(inaba@ms.utokyo.ac.jp)へご連絡ください．
Tsuyoshi Kajiwara (Professor Emeritus, Okayama University)
Destabilization induced by time delay, immunity and absorbing effect
(Japanese)
[ Reference URL ]
オンラインですので，参加希望のかたは稲葉(inaba@ms.utokyo.ac.jp)へご連絡ください．
2022/01/18
Operator Algebra Seminars
16:4518:15 Online
Miho Mukohara (Univ. Tokyo)
C$^*$simplicity of relative profinite completions of generalized BaumslagSolitar groups
[ Reference URL ]
https://www.ms.utokyo.ac.jp/~yasuyuki/tokyoseminar.htm
Miho Mukohara (Univ. Tokyo)
C$^*$simplicity of relative profinite completions of generalized BaumslagSolitar groups
[ Reference URL ]
https://www.ms.utokyo.ac.jp/~yasuyuki/tokyoseminar.htm
TokyoNagoya Algebra Seminar
15:0016:30 Online
Please see the URL below for details on the online seminar.
Haruhisa Enomoto (Osaka Prefecture University)
Exactcategorical properties of subcategories of abelian categories 1 (Japanese)
http://www.math.nagoyau.ac.jp/~aaron.chan/TNAseminar.html
Please see the URL below for details on the online seminar.
Haruhisa Enomoto (Osaka Prefecture University)
Exactcategorical properties of subcategories of abelian categories 1 (Japanese)
[ Abstract ]
Quillen's exact category is a powerful framework for studying extensionclosed subcategories of abelian categories, and provides many interesting questions on such subcategories.
In the first talk, I will explain the basics of some properties and invariants of exact categories (e.g. the JordanHolder property, simple objects, and Grothendieck monoid).
In the second talk, I will give some results and questions about particular classes of exact categories arising in the representation theory of algebras (e.g. torsion(free) classes over path algebras and preprojective algebras).
If time permits, I will discuss questions of whether these results can be generalized to extriangulated categories (extensionclosed subcategories of triangulated categories).
[ Reference URL ]Quillen's exact category is a powerful framework for studying extensionclosed subcategories of abelian categories, and provides many interesting questions on such subcategories.
In the first talk, I will explain the basics of some properties and invariants of exact categories (e.g. the JordanHolder property, simple objects, and Grothendieck monoid).
In the second talk, I will give some results and questions about particular classes of exact categories arising in the representation theory of algebras (e.g. torsion(free) classes over path algebras and preprojective algebras).
If time permits, I will discuss questions of whether these results can be generalized to extriangulated categories (extensionclosed subcategories of triangulated categories).
http://www.math.nagoyau.ac.jp/~aaron.chan/TNAseminar.html
Lie Groups and Representation Theory
17:0018:00 Room #On line (Graduate School of Math. Sci. Bldg.)
Hideyuki Ishi (Osaka City University)
Strongly visible actions on complex domains (Japanese)
Hideyuki Ishi (Osaka City University)
Strongly visible actions on complex domains (Japanese)
[ Abstract ]
In this century, the CartanHartogs domain and its variations, on which the Bergman kernel function and the KahlerEinstein metric can be computed explicitly, have been actively studied. Reasoning that strongly visible actions on the domains enable such nice calculations, we introduce a new type of complex domain analogous to the CartanHartogs domain, and present a research plan about harmonic analysis over the domain.
In this century, the CartanHartogs domain and its variations, on which the Bergman kernel function and the KahlerEinstein metric can be computed explicitly, have been actively studied. Reasoning that strongly visible actions on the domains enable such nice calculations, we introduce a new type of complex domain analogous to the CartanHartogs domain, and present a research plan about harmonic analysis over the domain.
2022/01/13
Information Mathematics Seminar
16:5018:35 Online
Keita Xagawa (NTT)
Latticebased cryptography and its applications (Japanese)
https://docs.google.com/forms/d/1WLEbsA2aQTXgdE2ynrumJOGZ4AVWqcOLCz42B4nPY
Keita Xagawa (NTT)
Latticebased cryptography and its applications (Japanese)
[ Abstract ]
Explanation on latticebased cryptography and its applications
[ Reference URL ]Explanation on latticebased cryptography and its applications
https://docs.google.com/forms/d/1WLEbsA2aQTXgdE2ynrumJOGZ4AVWqcOLCz42B4nPY
2022/01/11
Operator Algebra Seminars
16:4518:15 Online
Akihiro Miyagawa (Kyoto University)
Rationality for operators in free semicircular elements
[ Reference URL ]
https://www.ms.utokyo.ac.jp/~yasuyuki/tokyoseminar.htm
Akihiro Miyagawa (Kyoto University)
Rationality for operators in free semicircular elements
[ Reference URL ]
https://www.ms.utokyo.ac.jp/~yasuyuki/tokyoseminar.htm
Tuesday Seminar on Topology
17:0018:00 Online
Joint with Lie Groups and Representation Theory Seminar. See our seminar webpage.
Keiichi Maeta (The Univesity of Tokyo)
On the existence problem of Compact CliffordKlein forms of indecomposable pseudoRiemannian symmetric spaces with signature (n,2) (JAPANESE)
https://park.itc.utokyo.ac.jp/MSF/topology/TuesdaySeminar/index_e.html
Joint with Lie Groups and Representation Theory Seminar. See our seminar webpage.
Keiichi Maeta (The Univesity of Tokyo)
On the existence problem of Compact CliffordKlein forms of indecomposable pseudoRiemannian symmetric spaces with signature (n,2) (JAPANESE)
[ Abstract ]
For a homogeneous space $G/H$ and its discontinuous group $\Gamma\subset G$, the double coset space $\Gamma\backslash G/H$ is called a CliffordKlein form of $G/H$. In the study of CliffordKlein forms, the classification of homogeneous spaces which admit compact Clifford—Klein forms is one of the important open problems, which was introduced by Toshiyuki Kobayashi in 1980s. We consider this problem for indecomposable and reducible pseudoRiemannian symmetric spaces with signature (n,2). We show the nonexistence of compact CliffordKlein forms for some series of symmetric spaces, and construct new compact CliffordKlein forms of countably infinite fivedimensional pseudoRiemannian symmetric spaces with signature (3,2).
[ Reference URL ]For a homogeneous space $G/H$ and its discontinuous group $\Gamma\subset G$, the double coset space $\Gamma\backslash G/H$ is called a CliffordKlein form of $G/H$. In the study of CliffordKlein forms, the classification of homogeneous spaces which admit compact Clifford—Klein forms is one of the important open problems, which was introduced by Toshiyuki Kobayashi in 1980s. We consider this problem for indecomposable and reducible pseudoRiemannian symmetric spaces with signature (n,2). We show the nonexistence of compact CliffordKlein forms for some series of symmetric spaces, and construct new compact CliffordKlein forms of countably infinite fivedimensional pseudoRiemannian symmetric spaces with signature (3,2).
https://park.itc.utokyo.ac.jp/MSF/topology/TuesdaySeminar/index_e.html
Lie Groups and Representation Theory
17:0018:00 Room #on line (Graduate School of Math. Sci. Bldg.)
Joint with Tuesday Seminar on Topology.
Keiichi Maeta (The University of Tokyo)
On the existence problem of Compact CliffordKlein forms of indecomposable pseudoRiemannian symmetric spaces with signature (n,2) (Japanese)
Joint with Tuesday Seminar on Topology.
Keiichi Maeta (The University of Tokyo)
On the existence problem of Compact CliffordKlein forms of indecomposable pseudoRiemannian symmetric spaces with signature (n,2) (Japanese)
[ Abstract ]
For a homogeneous space $G/H$ and its discontinuous group $\Gamma\subset G$, the double coset space $\Gamma\backslash G/H$ is called a CliffordKlein form of $G/H$. In the study of CliffordKlein forms, the classification of homogeneous spaces which admit compact CliffordKlein forms is one of the important open problems, which was introduced by Toshiyuki Kobayashi in 1980s.
We consider this problem for indecomposable and reducible pseudoRiemannian symmetric spaces with signature (n,2). We show the nonexistence of compact CliffordKlein forms for some series of symmetric spaces, and construct new compact CliffordKlein forms of countably infinite fivedimensional pseudoRiemannian symmetric spaces with signature (3,2).
For a homogeneous space $G/H$ and its discontinuous group $\Gamma\subset G$, the double coset space $\Gamma\backslash G/H$ is called a CliffordKlein form of $G/H$. In the study of CliffordKlein forms, the classification of homogeneous spaces which admit compact CliffordKlein forms is one of the important open problems, which was introduced by Toshiyuki Kobayashi in 1980s.
We consider this problem for indecomposable and reducible pseudoRiemannian symmetric spaces with signature (n,2). We show the nonexistence of compact CliffordKlein forms for some series of symmetric spaces, and construct new compact CliffordKlein forms of countably infinite fivedimensional pseudoRiemannian symmetric spaces with signature (3,2).
2022/01/06
Information Mathematics Seminar
16:5018:35 Online
Hiroshi Fujiwara (BroadBand Tower, Inc.)
Next cyber security strategy of the Japanese Government (Japanese)
https://docs.google.com/forms/d/1I3XD63V937BT_IoqRWBVN67goQAtbkSoIKs6hfLUAM
Hiroshi Fujiwara (BroadBand Tower, Inc.)
Next cyber security strategy of the Japanese Government (Japanese)
[ Abstract ]
Explanation on next cyber security strategy of the Japanese government
[ Reference URL ]Explanation on next cyber security strategy of the Japanese government
https://docs.google.com/forms/d/1I3XD63V937BT_IoqRWBVN67goQAtbkSoIKs6hfLUAM
2021/12/23
Information Mathematics Seminar
16:5018:35 Online
Hiroshi Fujiwara (BroadBand Tower, Inc.)
The cyber attack to the Ministry of Defenseaffiliated company and zero trust of Amazon/Google (Japanese)
https://docs.google.com/forms/d/1I3XD63V937BT_IoqRWBVN67goQAtbkSoIKs6hfLUAM
Hiroshi Fujiwara (BroadBand Tower, Inc.)
The cyber attack to the Ministry of Defenseaffiliated company and zero trust of Amazon/Google (Japanese)
[ Abstract ]
Explanation on the cyber attack to the Ministry of Defenseaffiliated company and zero trust of Amazon/Google
[ Reference URL ]Explanation on the cyber attack to the Ministry of Defenseaffiliated company and zero trust of Amazon/Google
https://docs.google.com/forms/d/1I3XD63V937BT_IoqRWBVN67goQAtbkSoIKs6hfLUAM
2021/12/22
Number Theory Seminar
17:0018:00 Online
Stefano Morra (Paris 8 University)
Some properties of the Hecke eigenclasses of the mod pcohomology of Shimura curves (English)
Stefano Morra (Paris 8 University)
Some properties of the Hecke eigenclasses of the mod pcohomology of Shimura curves (English)
[ Abstract ]
The mod p local Langlands program, foreseen by Serre and proposed in precise terms by C. Breuil after his pdivisible groups computations in the BreuilConradDiamondTaylor proof of the ShimuraTaiyamaWeil conjecture, was realized in the particular case of GL_2(\mathbf{Q}_p) thanks to a vast convergence of new tools: classification of mod prepresentations of GL_2(\mathbf{Q}_p), local Galois deformation techniques, localglobal compatibility arguments.
When trying to extend these conjectures to more general groups, multiple problems arise (lack of classification results for smooth mod prepresentations of padic groups, absence of explicit integral models for Galois representations with the relevant padic Hodge theory conditions), and the only way to formulate, and test, conjectures on a mod p local Langlands correspondence relies on its expected realization in Hecke eigenclasses of Shimura varieties (or, in other words, the expectation of a localglobal compatibility of the Langlands correspondence).
In this talk we describe some properties of Hecke isotypical spaces of the mod pcohomology of Shimura curves with infinite level at p, when the reflex field F is unramified at p and the Shimura curve arises from a quaternion algebra which is split at p. These Hecke isotypical spaces are expected to be the “good” smooth mod prepresentations of GL_2(F_{\mathfrak{p}}) attached to mod p Galois representations of Gal(\overline{\mathbf{Q}_p}/F_{\mathfrak{p}}) via the expected local Langlands correspondence mod p. We will in particular comment on their GelfandKirillov dimension, and their irreducibility (in particular, the finite length of these Hecke eigenspaces as GL_2(F_{\mathfrak{p}})representations).
This is a report on a series of work joint with C. Breuil, F. Herzig, Y. Hu et B. Schraen.
The mod p local Langlands program, foreseen by Serre and proposed in precise terms by C. Breuil after his pdivisible groups computations in the BreuilConradDiamondTaylor proof of the ShimuraTaiyamaWeil conjecture, was realized in the particular case of GL_2(\mathbf{Q}_p) thanks to a vast convergence of new tools: classification of mod prepresentations of GL_2(\mathbf{Q}_p), local Galois deformation techniques, localglobal compatibility arguments.
When trying to extend these conjectures to more general groups, multiple problems arise (lack of classification results for smooth mod prepresentations of padic groups, absence of explicit integral models for Galois representations with the relevant padic Hodge theory conditions), and the only way to formulate, and test, conjectures on a mod p local Langlands correspondence relies on its expected realization in Hecke eigenclasses of Shimura varieties (or, in other words, the expectation of a localglobal compatibility of the Langlands correspondence).
In this talk we describe some properties of Hecke isotypical spaces of the mod pcohomology of Shimura curves with infinite level at p, when the reflex field F is unramified at p and the Shimura curve arises from a quaternion algebra which is split at p. These Hecke isotypical spaces are expected to be the “good” smooth mod prepresentations of GL_2(F_{\mathfrak{p}}) attached to mod p Galois representations of Gal(\overline{\mathbf{Q}_p}/F_{\mathfrak{p}}) via the expected local Langlands correspondence mod p. We will in particular comment on their GelfandKirillov dimension, and their irreducibility (in particular, the finite length of these Hecke eigenspaces as GL_2(F_{\mathfrak{p}})representations).
This is a report on a series of work joint with C. Breuil, F. Herzig, Y. Hu et B. Schraen.
2021/12/21
Tuesday Seminar on Topology
17:3018:30 Online
Joint with Lie Groups and Representation Theory Seminar. See our seminar webpage.
Hiroki Shimakura (Tohoku University)
Classification of holomorphic vertex operator algebras of central charge 24 (JAPANESE)
https://park.itc.utokyo.ac.jp/MSF/topology/TuesdaySeminar/index_e.html
Joint with Lie Groups and Representation Theory Seminar. See our seminar webpage.
Hiroki Shimakura (Tohoku University)
Classification of holomorphic vertex operator algebras of central charge 24 (JAPANESE)
[ Abstract ]
Holomorphic vertex operator algebras are imporant in vertex operator algebra theory. For example, the famous moonshine vertex operator algebra is holomorphic. One of the fundamental problems is to classify holomorphic vertex operator algebras. It is known that holomorphic vertex operator algebras of central charge 8 and 16 are lattice vertex operator algebras. I will talk about recent progress on the classification of holomorphic vertex operator algebras of central charge 24.
[ Reference URL ]Holomorphic vertex operator algebras are imporant in vertex operator algebra theory. For example, the famous moonshine vertex operator algebra is holomorphic. One of the fundamental problems is to classify holomorphic vertex operator algebras. It is known that holomorphic vertex operator algebras of central charge 8 and 16 are lattice vertex operator algebras. I will talk about recent progress on the classification of holomorphic vertex operator algebras of central charge 24.
https://park.itc.utokyo.ac.jp/MSF/topology/TuesdaySeminar/index_e.html
Operator Algebra Seminars
16:4518:15 Online
Wojciech Dybalski (Adam Mickiewicz University in Poznan)
Interacting massless infraparticles in 1+1 dimensions
(English)
[ Reference URL ]
https://www.ms.utokyo.ac.jp/~yasuyuki/tokyoseminar.htm
Wojciech Dybalski (Adam Mickiewicz University in Poznan)
Interacting massless infraparticles in 1+1 dimensions
(English)
[ Reference URL ]
https://www.ms.utokyo.ac.jp/~yasuyuki/tokyoseminar.htm
Lie Groups and Representation Theory
17:3018:30 Room #on line (Graduate School of Math. Sci. Bldg.)
Joint with Tuesday Seminar on Topology.
Hiroki Shimakura (Tohoku University)
Classification of holomorphic vertex operator algebras of central charge 24
(Japanese)
Joint with Tuesday Seminar on Topology.
Hiroki Shimakura (Tohoku University)
Classification of holomorphic vertex operator algebras of central charge 24
(Japanese)
[ Abstract ]
Holomorphic vertex operator algebras are important in vertex operator algebra theory. For example, the famous moonshine vertex operator algebra is holomorphic.
One of the fundamental problems is to classify holomorphic vertex operator algebras. It is known that holomorphic vertex operator algebras of central charge 8 and 16 are lattice vertex operator algebras.
I will talk about recent progress on the classification of holomorphic vertex operator algebras of central charge 24.
Holomorphic vertex operator algebras are important in vertex operator algebra theory. For example, the famous moonshine vertex operator algebra is holomorphic.
One of the fundamental problems is to classify holomorphic vertex operator algebras. It is known that holomorphic vertex operator algebras of central charge 8 and 16 are lattice vertex operator algebras.
I will talk about recent progress on the classification of holomorphic vertex operator algebras of central charge 24.
2021/12/17
Colloquium
15:3016:30 Online
Registration is closed (12:00, December 17).
JunMuk Hwang (Center for Complex Geometry, IBS, Korea)
Growth vectors of distributions and lines on projective hypersurfaces (ENGLISH)
Registration is closed (12:00, December 17).
JunMuk Hwang (Center for Complex Geometry, IBS, Korea)
Growth vectors of distributions and lines on projective hypersurfaces (ENGLISH)
[ Abstract ]
For a distribution on a manifold, its growth vector is a finite sequence of integers measuring the dimensions of the directions spanned by successive Lie brackets of local vector fields belonging to the distribution. The growth vector is the most basic invariant of a distribution, but it is sometimes hard to compute. As an example, we discuss natural distributions on the spaces of lines covering hypersurfaces of low degrees in the complex projective space. We explain the ideas in a joint work with Qifeng Li where the growth vector is determined for lines on a general hypersurface of degree 4 and dimension 5.
For a distribution on a manifold, its growth vector is a finite sequence of integers measuring the dimensions of the directions spanned by successive Lie brackets of local vector fields belonging to the distribution. The growth vector is the most basic invariant of a distribution, but it is sometimes hard to compute. As an example, we discuss natural distributions on the spaces of lines covering hypersurfaces of low degrees in the complex projective space. We explain the ideas in a joint work with Qifeng Li where the growth vector is determined for lines on a general hypersurface of degree 4 and dimension 5.
2021/12/16
Applied Analysis
16:0017:00 Online
Zhanpeisov Erbol ( )
Existence of solutions for fractional semilinear parabolic equations in BesovMorrey spaces (Japanese)
[ Reference URL ]
https://forms.gle/whpkgAwYvyQKQMzM8
Zhanpeisov Erbol ( )
Existence of solutions for fractional semilinear parabolic equations in BesovMorrey spaces (Japanese)
[ Reference URL ]
https://forms.gle/whpkgAwYvyQKQMzM8
TokyoNagoya Algebra Seminar
16:4518:15 Online
Please see the URL below for details on the online seminar.
Nicholas Williams (University of Cologne)
Cyclic polytopes and higher AuslanderReiten theory (English)
http://www.math.nagoyau.ac.jp/~aaron.chan/TNAseminar.html
Please see the URL below for details on the online seminar.
Nicholas Williams (University of Cologne)
Cyclic polytopes and higher AuslanderReiten theory (English)
[ Abstract ]
Oppermann and Thomas show that tilting modules over Iyama’s higher Auslander algebras of type A are in bijection with triangulations of evendimensional cyclic polytopes. Triangulations of cyclic polytopes are partially ordered in two natural ways known as the higher StasheffTamari orders, which were introduced in the 1990s by Kapranov, Voevodsky, Edelman, and Reiner as higherdimensional generalisations of the Tamari lattice. These two partial orders were conjectured to be equal in 1996 by Edelman and Reiner, and we prove that this conjecture is true. We further show how the higher StasheffTamari orders correspond in even dimensions to natural orders on tilting modules which were studied by Riedtmann, Schofield, Happel, and Unger. This then allows us to complete the picture of Oppermann and Thomas by showing that triangulations of odddimensional cyclic polytopes correspond to equivalence classes of dmaximal green sequences, which we introduce as higherdimensional analogues of Keller’s maximal green sequences. We show that the higher StasheffTamari orders correspond to natural orders on equivalence classes of dmaximal green sequences, which relate to the nogap conjecture of Brustle, Dupont, and Perotin. The equality of the higher StasheffTamari orders then implies that these algebraic orders on tilting modules and dmaximal green sequences are equal. If time permits, we will also discuss some results on mutation of clustertilting objects and triangulations.
[ Reference URL ]Oppermann and Thomas show that tilting modules over Iyama’s higher Auslander algebras of type A are in bijection with triangulations of evendimensional cyclic polytopes. Triangulations of cyclic polytopes are partially ordered in two natural ways known as the higher StasheffTamari orders, which were introduced in the 1990s by Kapranov, Voevodsky, Edelman, and Reiner as higherdimensional generalisations of the Tamari lattice. These two partial orders were conjectured to be equal in 1996 by Edelman and Reiner, and we prove that this conjecture is true. We further show how the higher StasheffTamari orders correspond in even dimensions to natural orders on tilting modules which were studied by Riedtmann, Schofield, Happel, and Unger. This then allows us to complete the picture of Oppermann and Thomas by showing that triangulations of odddimensional cyclic polytopes correspond to equivalence classes of dmaximal green sequences, which we introduce as higherdimensional analogues of Keller’s maximal green sequences. We show that the higher StasheffTamari orders correspond to natural orders on equivalence classes of dmaximal green sequences, which relate to the nogap conjecture of Brustle, Dupont, and Perotin. The equality of the higher StasheffTamari orders then implies that these algebraic orders on tilting modules and dmaximal green sequences are equal. If time permits, we will also discuss some results on mutation of clustertilting objects and triangulations.
http://www.math.nagoyau.ac.jp/~aaron.chan/TNAseminar.html
Information Mathematics Seminar
16:5018:35 Online
Hiroshi Fujiwara (BroadBand Tower, Inc.)
The cyber attack to a car company supply chain network and Zero trust by the Cisco Systems (Japanese)
https://docs.google.com/forms/d/1I3XD63V937BT_IoqRWBVN67goQAtbkSoIKs6hfLUAM
Hiroshi Fujiwara (BroadBand Tower, Inc.)
The cyber attack to a car company supply chain network and Zero trust by the Cisco Systems (Japanese)
[ Abstract ]
Explanation on the cyber attack to the supply chain network of car company and zero trust by the Cisco Systems
[ Reference URL ]Explanation on the cyber attack to the supply chain network of car company and zero trust by the Cisco Systems
https://docs.google.com/forms/d/1I3XD63V937BT_IoqRWBVN67goQAtbkSoIKs6hfLUAM
2021/12/14
Operator Algebra Seminars
16:4518:15 Online
Karen Strung (Czech Academy of Science)
Constructions in minimal amenable dynamics and applications to classification of $C^*$algebras
[ Reference URL ]
https://www.ms.utokyo.ac.jp/~yasuyuki/tokyoseminar.htm
Karen Strung (Czech Academy of Science)
Constructions in minimal amenable dynamics and applications to classification of $C^*$algebras
[ Reference URL ]
https://www.ms.utokyo.ac.jp/~yasuyuki/tokyoseminar.htm
Lie Groups and Representation Theory
17:0018:00 Room #on line (Graduate School of Math. Sci. Bldg.)
Yosuke Morita (Kyoto University)
On the definition of Conley indices (Japanese)
Yosuke Morita (Kyoto University)
On the definition of Conley indices (Japanese)
[ Abstract ]
Conley indices are used to describe local behaviour of topological dynamical systems. In this talk, I will explain a new framework for Conley index theory. Our approach is very elementary, and uses only general topology and some computations of inclusion relations of subsets.
Conley indices are used to describe local behaviour of topological dynamical systems. In this talk, I will explain a new framework for Conley index theory. Our approach is very elementary, and uses only general topology and some computations of inclusion relations of subsets.
123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167 Next >