LOCALLY DERIVED GRAPHS

Speaker(s)

MARIUSZ TOBOLSKI

Affiliation

Uniwersytet Wrocławski, Wrocław, Poland

Language of the talk

English

Date

Nov. 5, 2025, 5:15 p.m.

Information about the event

IMPAN - Room 405 & zoom

Title in Polish

LOCALLY DERIVED GRAPHS

Seminar

North Atlantic Noncommutative Geometry Seminar

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Voltage and derived graphs (also called base and skew product graphs, respectively) were introduced by Gross and Tucker to study free actions of groups on graphs. These notions found applications in the theory of C*-algebras when Kumjian and Pask showed that crossed products of graph C*-algebras by actions induced from group actions on graphs are isomorphic to C*-algebras of the corresponding derived graphs. In this talk, we introduce the concept of locally derived graphs, which substantially extends the paradigm of derived graphs, and use the projection foldings from locally derived graphs to their base graphs to obtain one-surjective pullbacks of graph C*-algebras. Based on joint work with Piotr M. Hajac.

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