English

Gabor Frames for Quasicrystals, $K$-theory, and Twisted Gap Labeling

Operator Algebras 2017-09-07 v1 Functional Analysis K-Theory and Homology

Abstract

We study the connection between Gabor frames for quasicrystals, the topology of the hull of a quasicrystal Λ,\Lambda, and the KK-theory of the twisted groupoid CC^*-algebra Aσ\mathcal{A}_\sigma arising from a quasicrystal. In particular, we construct a finitely generated projective module H\L\mathcal{H}_\L over Aσ\mathcal{A}_\sigma related to time-frequency analysis, and any multiwindow Gabor frame for Λ\Lambda can be used to construct an idempotent in MN(Aσ)M_N(\mathcal{A}_\sigma) representing H\L\mathcal{H}_\L in K0(Aσ).K_0(\mathcal{A}_\sigma). We show for lattice subsets in dimension two, this element corresponds to the Bott element in K0(Aσ),K_0(\mathcal{A}_\sigma), allowing us to prove a twisted version of Bellissard's gap labeling theorem.

Keywords

Cite

@article{arxiv.1411.7269,
  title  = {Gabor Frames for Quasicrystals, $K$-theory, and Twisted Gap Labeling},
  author = {Michael Kreisel},
  journal= {arXiv preprint arXiv:1411.7269},
  year   = {2017}
}
R2 v1 2026-06-22T07:13:17.544Z