English

Every graded ideal of a Leavitt path algebra is graded isomorphic to a Leavitt path algebra

Rings and Algebras 2022-11-23 v3

Abstract

We show that every graded ideal of a Leavitt path algebra is graded isomorphic to a Leavitt path algebra. It is known that a graded ideal II of a Leavitt path algebra is isomorphic to the Leavitt path algebra of a graph, known as the generalized hedgehog graph, which is defined based on certain sets of vertices uniquely determined by II. However, this isomorphism may not be graded. We show that replacing the short "spines" of the generalized hedgehog graph with possibly fewer, but then necessarily longer spines, we obtain a graph (which we call the porcupine graph) such that its Leavitt path algebra is graded isomorphic to II. Our proof adapts to show that for every closed gauge-invariant ideal JJ of a graph CC^*-algebra, there is a gauge-invariant *-isomorphism mapping the graph CC^*-algebra of the porcupine graph of JJ onto J.J.

Keywords

Cite

@article{arxiv.2106.14828,
  title  = {Every graded ideal of a Leavitt path algebra is graded isomorphic to a Leavitt path algebra},
  author = {Lia Vas},
  journal= {arXiv preprint arXiv:2106.14828},
  year   = {2022}
}