[geometry-ml:05270] 東北大学幾何学セミナー

[本多正平]

幾何学メーリングリストのみなさま，

東北大学の本多正平と申します．
イレギュラーですが，8月7日(月)の13時から東北大にて以下の3つの幾何学セミナーを対面で企画しておりますので，その案内を流しております；

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8月7日(月) 13:00〜17:30 ※時間と場所が通常とは異なります
形式：対面（数学棟201号室）
スケジュール：
13:00-14:00 Elia Brue (Bocconi University)
14:30-15:30 Qin Deng (MIT)
16:00-17:00 Chiara Rigoni (University of Vienna)


講演者：Elia Brue氏（Bocconi University）
タイトル：Collapsing under lower curvature bounds and topological stability
概要：The study of collapsing Riemannian manifolds under various
curvature constraints is a topic of profound interest in geometric
analysis. After a brief introduction to the subject, I will present a
new topological stability result. Specifically, I will demonstrate
that a sequence of tori with a uniform diameter and lower scalar
curvature bound converges to a torus.

This is based on joint work with A. Naber and D. Semola.

講演者：Qin Deng氏（MIT）
タイトル：Margulis Lemma on RCD spaces
概要：The generalized Margulis Lemma for manifolds with Ricci curvature
bounded from below proved by Kapovitch-Wilking states that the
subgroup of the fundamental group generated by small loops around a
given point is virtually nilpotent. In this talk, I will extend this
result to RCD spaces, which are nonsmooth metric measure spaces
satisfying a synthetic notion of Ricci curvature bounded from below.
To do so, I will discuss some new regularity results for Regular
Lagrangian flows, which are flows of nonsmooth vector fields, on RCD
spaces. This is joint work with Sergio Zamora, Jaime Santos and Xinrui
Zhao.

講演者：Chiara Rigoni氏（University of Vienna）
タイトル：Convergence of metric measure spaces satisfying the CD condition
for negative values of the dimensional parameter
概要：In this talk, we show the stability of the curvature-dimension
condition for negative values of the generalized dimension parameter
under a suitable notion of convergence. We start by presenting an
appropriate setting to introduce the CD(K, N)-condition for N < 0,
allowing metric measure structures in which the reference measure is
quasi-Radon. Then in this class of spaces we introduce the distance
$d_{\mathsf{iKRW}}$, which extends the already existing notions of
distance between metric measure spaces. Finally, we prove that if a
sequence of metric measure spaces satisfying the CD(K, N)-condition
with N < 0 is converging with respect to the distance
$d_{\mathsf{iKRW}}$ to some metric measure space, then this limit
structure is still a CD(K, N) space. This talk is based on a joint
work with M. Magnabosco and G. Sosa.
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詳しい情報は次のページでも見ることができます；

https://sites.google.com/site/aobageometry/

本多正平