セミナー情報

今週のセミナー

  • 2018.2.20(火) | セミナー

    幾何セミナー(15:00--16:30【会場:数学棟305】

    講演者: Martin Guest 氏(早稲田大学)
    題目:The enhanced Coxeter Plane - an application of integrable systems to Lie groups
    概要:
    The Dynkin Diagram and the Stiefel Diagram are "visualizations" of Lie groups (or their root systems) which are very familiar to geometers and topologists. We propose an "enhanced" Coxeter Plane as a third visualization. This has a purely Lie-theoretic definition, but it arises most naturally from a certain isomonodromic family of meromorphic connections, constructed as a special case of the Toda equations - an integrable system. This is joint work with Nan-Kuo Ho.
    幾何セミナーの情報はこちら

  • 2018.2.22(木)| セミナー

    代数セミナー(13:30--16:45【会場:数学棟209】

    (1)13:30--15:00
    講演者:岩佐 亮明 氏(東京大学大学院数理科学研究科)
    題目:Relative homotopy K-theory and algebraic cycles with moduli
    概要:
    Relative homotopy K-theory and algebraic cycles with moduli 概要: This is a joint work with Amalendu Krishna. Recall that Bloch's higher cycle group Z*(X;r) of an algebraic scheme X is a free abelian group (graded by codimension) generated by integral closed subschemes of X × Δr meeting all the faces properly. Given a closed subset D of X, we consider the subgroup Z*(X,D;r) of Z*(X;r) generated by those cycles which do not meet D×Δr. Then it is assembled into a simplicial abelian group Z*(X,D;-) and we denote its n-th homotopy group by CH*(X,D;n). In this talk, I explain that CH*(X,D;n) is related to the relative homotopy K-theory KH(X,D) as Bloch's higher Chow group CH*(X;n) is related to the K-theory K(X). More precisely, under some general hypotheses, we establish an Atiyah- Hirzebruch type spectral sequence relating them.
    (2)15:15--16:45
    講演者:中村 健太郎 氏 (佐賀大学大学院工学系研究科)
    題目:階数2の普遍ガロア変形に対するゼータ同型の構成に向けて
    概要:
    加藤和也氏による一般化岩澤主予想によれば, 大域的なp進ガロア表現の任意の族のガロアコホモロジーに対して, ゼータ同型と呼ばれる標準的な基底が存在することが予想されている. ゼータ同型はオイラー系の存在と密接に関係しており, 現在までに, 階数1のガロア表現の族の場合(円単数のオイラー系を用いて定義される) と楕円保型形式に付随するガロア表現の円分変形の場合(加藤氏のオイラー系を用いて定義される), さらには楕円保型形式の肥田族に付随するガロア表現の場合(深谷-加藤-Sharifi氏による最近の結果) などに構成されている. 今回の話では, モジュラー曲線の完備コホモロジーとp進局所 ラングランズ対応との関係に関するCaraiani-Emerton-Gee-Geraghty-Paskunas-Shin らの結果を用いて, 階数2の普遍ガロア変形の場合にゼータ同型を構成するアイデアについて話したい. このアイデアを実行するためには, 深谷-加藤-Sharifi氏による ゼータ同型の整数性に関する結果の類似を完備コホモロジーの場合へ拡張することが必要になる. この問題点(まだ解決できていない)についても解説したい.
    代数セミナーの情報はこちら



来週以降のセミナー

  • 2018.3.7~3.9 | セミナー

    幾何セミナー Intensive lectures(Special Talk Series)【会場:数学棟305、数学棟201】

    Jayadev Athreya 氏(University of Washington, Seattle, US)
    Equivariant Point Processes, Lattices, and Flat Surfaces
    7日、8日 14:00--15:30 数学棟 305
    9日 11:00--12:30 数学棟 201
    概要:
    We describe a general framework of equivariant point processes, also known as Siegel Measures, introduced by W. Veech, as a tool with which to study lattice and translation surfaces in a unified framework. We will introduce the space of lattices and the space of translation surfaces, and discuss counting and ergodic problems. We assume no background beyond some basic measure theory and complex analysis, and will attempt to make our lectures as self-contained as possible.
    幾何セミナーの情報はこちら

  • 2018.3.22(木)| セミナー

    代数セミナー(13:30--16:45【会場:数学棟209】

    (1)13:30--15:00
    講演者:志甫 淳 氏(東京大学大学院数理科学研究科)
    題目:
    (2)15:15--16:45
    講演者:Toan M. Nguyen 氏 (Univasität Osnabrück)
    題目:Orbifold motivic cohomology and K-theory
    概要:
    In this talk, I will discuss new algebraic invariants for algebraic orbifolds: orbifold motivic cohomology and orbifold K-theory. These invariants come out as a consequence of the obstruction bundles and the virtual fundamental classes in Gromov-Witten theory. I will also explain how these invariants relate to motivic cohomology and K-theory of (crepant) resolutions of singularities of the coarse moduli spaces of orbifolds. This is a joint work with Lie Fu.
    代数セミナーの情報はこちら


過去の記録

2017年度

  • 2018.2.8(木)| セミナー

    微分方程式特別セミナー(14:00--16:30【会場:合同A棟801】

    (1)14:00~15:00
    講演者: Mikolaj Sierzega 氏(University of Warsaw)
    題目:Li-Yau-Hamilton type inequalities and their application to the regularity theory for the Fujita equation
    概要:
    Li-Yau-Hamilton type inequalities lie at the heart of the regularity theory for the Ricci flow. Somewhat unexpectedly they appear to be also central to the regularity theory for "flat" semilinear parabolic equations. In my talk I will sketch how these extraordinary inequalities emerge in the study of blow-ups for the Fujita equation.
    (2)15:30--16:30
    講演者:Minjie Shan 氏(Kyoto University)
    題目:Local well-posedness for the two-dimensional Zakharov-Kuznetsov equation
    微分方程式特別セミナーの情報はこちら

  • 2018.2.13(火) | セミナー

    幾何セミナー(15:00--16:30【会場:数学棟305】

    講演者: Rafael Monteiro 氏(MathAM-OIL)
    題目:Phase separation patterns from directional quenching
    概要:
    In this talk I describe the effect of directional quenching on patterns formed in simple bistable systems such as the Allen-Cahn and the Cahn-Hilliard equation on the plane. Directional quenching is considered as an externally triggered change in system parameters, changing the system from monostable to bistable across an interface; numerically and experimentally, one can see patterns forming in the bistable region, in particular as the trigger progresses and increases the bistable region. I will discuss existence and non-existence results of single interfaces and striped patterns, focusing on the multi-d case. If time allows I will discuss more recent work on contact angle selection for interfaces in growing domains. Joint work with Arnd Scheel (Univ. of Minnesota, USA).
    幾何セミナーの情報はこちら

  • 2018.2.16(金) | セミナー

    代数幾何学セミナー(15:00--16:00【会場:数学棟517】)

    講演者:石田 正典 氏 (東北大学大学院理学研究科)
    題目:トーリック型カスプ特異点の構成について

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