Subalgebras of Graph C*-Algebras
Abstract
We prove a spectral theorem for bimodules in the context of graph C*-algebras. A bimodule over a suitable abelian algebra is determined by its spectrum (i.e., its groupoid partial order) iff it is generated by the Cuntz-Krieger partial isometries which it contains iff it is invariant under the gauge automorphisms. We study 1-cocycles on the Cuntz-Krieger groupoid associated with a graph C*-algebra, obtaining results on when integer valued or bounded cocycles on the natural AF subgroupoid extend. To a finite graph with a total order, we associate a nest subalgebra of the graph C*-algebra and then determine its spectrum. This is used to investigate properties of the nest subalgebra. We give a characterization of the partial isometries in a graph C*-algebra which normalize a natural diagonal subalgebra and use this to show that guage invariant generating triangular subalgebras are classified by their spectra.
Keywords
Cite
@article{arxiv.math/0409075,
title = {Subalgebras of Graph C*-Algebras},
author = {Alan Hopenwasser and Jurtin R. Peters and Stephen C. Power},
journal= {arXiv preprint arXiv:math/0409075},
year = {2007}
}