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Future seminars
Seminar information archive ～06/10｜Today's seminar 06/11 | Future seminars 06/12～
2025/06/16
Seminar on Geometric Complex Analysis
10:30-12:00 Room #128 (Graduate School of Math. Sci. Bldg.)
Masakazu Takakura (Tokyo Metropolitan Univ.)
On the sharp $L^2$-estimate of Skoda division theorem (Japanese)
[ Reference URL ]
https://forms.gle/gTP8qNZwPyQyxjTj8
Masakazu Takakura (Tokyo Metropolitan Univ.)
On the sharp $L^2$-estimate of Skoda division theorem (Japanese)
[ Reference URL ]
https://forms.gle/gTP8qNZwPyQyxjTj8
2025/06/17
Operator Algebra Seminars
16:45-18:15 Room #117 (Graduate School of Math. Sci. Bldg.)
Hikaru Awazu (University of Tokyo)
Amenability of group actions on compact spaces and the associated Banach algebras
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
Hikaru Awazu (University of Tokyo)
Amenability of group actions on compact spaces and the associated Banach algebras
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
Tuesday Seminar on Topology
17:00-18:30 Room #ハイブリッド開催/056 (Graduate School of Math. Sci. Bldg.)
Pre-registration required. See our seminar webpage.
Taketo Sano (RIKEN iTHEMS)
A diagrammatic approach to the Rasmussen invariant via tangles and cobordisms (JAPANESE)
https://park.itc.u-tokyo.ac.jp/MSF/topology/TuesdaySeminar/index_e.html
Pre-registration required. See our seminar webpage.
Taketo Sano (RIKEN iTHEMS)
A diagrammatic approach to the Rasmussen invariant via tangles and cobordisms (JAPANESE)
[ Abstract ]
Rasmussen's s-invariant is an integer-valued knot invariant derived from Khovanov homology, and it has remarkable applications in topology, such as providing a combinatorial reproof of the Milnor conjecture. Although the s-invariant is defined using the quantum filtration of the homology group, it is difficult to interpret it geometrically. In this talk, we give a cobordism-based interpretation of the s-invariant based on Bar-Natan’s reformulation of Khovanov homology via tangles and cobordisms. This interpretation allows for the computation of the s-invariant from a tangle decomposition of the knot. As an application, we demonstrate that the s-invariants of a certain infinite family of pretzel knots can be determined by hand.
[ Reference URL ]Rasmussen's s-invariant is an integer-valued knot invariant derived from Khovanov homology, and it has remarkable applications in topology, such as providing a combinatorial reproof of the Milnor conjecture. Although the s-invariant is defined using the quantum filtration of the homology group, it is difficult to interpret it geometrically. In this talk, we give a cobordism-based interpretation of the s-invariant based on Bar-Natan’s reformulation of Khovanov homology via tangles and cobordisms. This interpretation allows for the computation of the s-invariant from a tangle decomposition of the knot. As an application, we demonstrate that the s-invariants of a certain infinite family of pretzel knots can be determined by hand.
Preprint: https://arxiv.org/abs/2503.05414
https://park.itc.u-tokyo.ac.jp/MSF/topology/TuesdaySeminar/index_e.html
2025/06/18
Number Theory Seminar
17:00-18:00 Room #117 (Graduate School of Math. Sci. Bldg.)
Liu Yuanmin (University of Tokyo)
p-Adic cohomology over Laurent series rings and weight spectral sequences of strictly semistable schemes (日本語 (Japanese))
Liu Yuanmin (University of Tokyo)
p-Adic cohomology over Laurent series rings and weight spectral sequences of strictly semistable schemes (日本語 (Japanese))
[ Abstract ]
Let $k$ be a field of characteristic $p > 0$. Berthelot defined the rigid cohomology for varieties over $k$ after the work of Monsky-Washnitzer and Dwork. He also consider the theory of arithmetic D-modules which should be the coefficients for rigid cohomology. His work is generalized by Lazda-Pál and Caro to theories over $k((t))$. I will talk about their generalization and the construction of weight spectral sequence of strictly semistable schemes using arithmetic D-modules.
Let $k$ be a field of characteristic $p > 0$. Berthelot defined the rigid cohomology for varieties over $k$ after the work of Monsky-Washnitzer and Dwork. He also consider the theory of arithmetic D-modules which should be the coefficients for rigid cohomology. His work is generalized by Lazda-Pál and Caro to theories over $k((t))$. I will talk about their generalization and the construction of weight spectral sequence of strictly semistable schemes using arithmetic D-modules.
2025/06/20
Colloquium
15:30-16:30 Room #大講義室(auditorium) (Graduate School of Math. Sci. Bldg.)
Yuichi Ike (Graduate School of Mathematical Sciences, The University of Tokyo)
The square peg problem and microlocal sheaf theory (JAPANESE)
Yuichi Ike (Graduate School of Mathematical Sciences, The University of Tokyo)
The square peg problem and microlocal sheaf theory (JAPANESE)
[ Abstract ]
The square peg problem asks whether every Jordan curve in the plane admits four distinct points that form the vertices of a square. This problem was proposed by Toeplitz in 1911, but it is still open. This problem can be generalized to the rectangular peg problem, which asks about the existence of a rectangle with a given aspect ratio. Greene and Lobb gave an affirmative answer to the rectangular peg problem for any smooth Jordan curve using symplectic geometry, and later improved the result using spectral invariants in Floer theory. In this talk, I will explain that we can solve the rectangular peg problem for any rectifiable Jordan curve using microlocal sheaf theory. This is joint work with Tomohiro Asano.
The square peg problem asks whether every Jordan curve in the plane admits four distinct points that form the vertices of a square. This problem was proposed by Toeplitz in 1911, but it is still open. This problem can be generalized to the rectangular peg problem, which asks about the existence of a rectangle with a given aspect ratio. Greene and Lobb gave an affirmative answer to the rectangular peg problem for any smooth Jordan curve using symplectic geometry, and later improved the result using spectral invariants in Floer theory. In this talk, I will explain that we can solve the rectangular peg problem for any rectifiable Jordan curve using microlocal sheaf theory. This is joint work with Tomohiro Asano.
2025/06/23
Seminar on Geometric Complex Analysis
10:30-12:00 Room #128 (Graduate School of Math. Sci. Bldg.)
Shoto Kikuchi (National Institute of Technology, Suzuka College)
TBA (Japanese)
[ Reference URL ]
https://forms.gle/gTP8qNZwPyQyxjTj8
Shoto Kikuchi (National Institute of Technology, Suzuka College)
TBA (Japanese)
[ Reference URL ]
https://forms.gle/gTP8qNZwPyQyxjTj8
2025/06/24
Operator Algebra Seminars
16:45-18:15 Room #117 (Graduate School of Math. Sci. Bldg.)
George Elliott (Univ. Toronto)
Recent progress in the classification of $C^*$-algebras
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
George Elliott (Univ. Toronto)
Recent progress in the classification of $C^*$-algebras
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
2025/06/26
Applied Analysis
16:00-17:30 Room #128 (Graduate School of Math. Sci. Bldg.)
Yang Yang (University of Wisconsin-Madison)
A half-space Bernstein theorem for anisotropic minimal graphs (English)
Yang Yang (University of Wisconsin-Madison)
A half-space Bernstein theorem for anisotropic minimal graphs (English)
[ Abstract ]
Anisotrpic functionals are the natural generalization of the area functional. From a technical perspective, what distinguishes general anisotropic functionals from the area case is the absence of a monotonicity formula. In this talk, we will present a proof of a half-space Bernstein theorem for anisotropic minimal graphs with flat boundary condition. The proof uses only the maximal principle and ideas from fully nonlinear PDE theory in lieu of a monotonicity formula. This is joint work with W. Du, C. Moony, and J. Zhu.
Anisotrpic functionals are the natural generalization of the area functional. From a technical perspective, what distinguishes general anisotropic functionals from the area case is the absence of a monotonicity formula. In this talk, we will present a proof of a half-space Bernstein theorem for anisotropic minimal graphs with flat boundary condition. The proof uses only the maximal principle and ideas from fully nonlinear PDE theory in lieu of a monotonicity formula. This is joint work with W. Du, C. Moony, and J. Zhu.
2025/07/01
Operator Algebra Seminars
16:45-18:15 Room #117 (Graduate School of Math. Sci. Bldg.)
Mao Hoshino (Univ. Tokyo)
A tensor categorical aspect of quantum group actions
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
Mao Hoshino (Univ. Tokyo)
A tensor categorical aspect of quantum group actions
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
2025/07/07
Seminar on Geometric Complex Analysis
10:30-12:00 Room #128 (Graduate School of Math. Sci. Bldg.)
Taiji Marugame (The Univ. of Electro-Communications)
TBA (Japanese)
[ Reference URL ]
https://forms.gle/gTP8qNZwPyQyxjTj8
Taiji Marugame (The Univ. of Electro-Communications)
TBA (Japanese)
[ Reference URL ]
https://forms.gle/gTP8qNZwPyQyxjTj8
2025/07/10
Geometric Analysis Seminar
14:00-15:00 Room #056 (Graduate School of Math. Sci. Bldg.)
Jeff Viaclovsky (University of California, Irvine)
TBA (英語)
Jeff Viaclovsky (University of California, Irvine)
TBA (英語)
[ Abstract ]
TBA
TBA
2025/09/09
Operator Algebra Seminars
16:45-18:15 Room #126 (Graduate School of Math. Sci. Bldg.)
Kang Li (FAU Erlangen-Nürnberg)
Dimension theories from groupoids to classifiable $C^*$-algebras, and back again
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/seminar/operalge/future.html
Kang Li (FAU Erlangen-Nürnberg)
Dimension theories from groupoids to classifiable $C^*$-algebras, and back again
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/seminar/operalge/future.html
