3 papers
math.OA2026
Voltage quantum graphs and a Gross-Tucker theorem for quantum graphs
Björn Schäfer, Mariusz Tobolski
A voltage graph is a finite directed graph whose edges are labeled by elements of a finite group . A classical construction of Gross and Tucker associates to every voltage graph…
math.OA2025
Hypercube C*-algebras and an application to magic isometries
Björn Schäfer
We study C*-algebras generated by two partitions of unity with orthogonality relations governed by hypercubes for . These "hypercube C*-alge…
math.OA2025
Classification of Certain C*-Algebras Generated by Two Partitions of Unity
Björn Schäfer
We study C*-algebras generated by two partitions of unity subject to orthogonality relations governed by a bipartite graph which we also call "bipartite graph C*-algebras". These a…