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BIMSA Topology Seminar
Nested homotopy models of finite metric spaces and their spectral homology
Nested homotopy models of finite metric spaces and their spectral homology
演讲者
时间
2024年01月22日 14:30 至 16:00
地点
A3-4-101
线上
Zoom 230 432 7880
(BIMSA)
摘要
For over a decade, two theories have been actively developed: theory of magnitude and magnitude homology of metric spaces, and GLMY-theory of path homology of directed graphs. Recently Asao showed that for the case of directed graphs there is a unified approach to these theories via a spectral sequence which is now known as the magnitude-path spectral sequence. He also introduced a notion of r-homotopy for directed graphs and proved that the r+1-st page of the spectral sequence is r-homotopy invariant. We extend this theory to the general case of quasimetric spaces that include metric spaces and directed graphs. We show that for a real number r and a finite quasimetric space X there is a unique (up to isometry) r-homotopy equivalent quasimetric space of the minimal possible cardinality. It is called the r-minimal model of X. We use this to construct a decomposition of the magnitude-path spectral sequence of a digraph into a direct sum of spectral sequences with certain properties. We also construct an r-homotopy invariant of a quasimetric space X called spectral homology, that generalizes many other invariants: the pages of the magnitude-path spectral sequence, including path homology, magnitude homology, blurred magnitude homology and reachability homology.
演讲者介绍
Sergei Ivanov教授是来自俄罗斯圣彼得堡的数学家。 他的研究兴趣包括同调代数、代数拓扑、群论、单纯同伦论和单纯群。