Browsing NTNU Open by Author "Austad, Are"
Now showing items 1-8 of 8
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C∗-uniqueness Results for Groupoids
Ortega Esparza, Eduardo; Austad, Are (Peer reviewed; Journal article, 2020)For a 2nd-countable locally compact Hausdorff étale groupoid G with a continuous 2-cocycle σ we find conditions that guarantee that ℓ1(G,σ) has a unique C∗-norm. -
Gabor duality theory for Morita equivalent C*-algebras
Austad, Are; Jakobsen, Mads Sielemann; Luef, Franz (Journal article; Peer reviewed, 2020)The duality principle for Gabor frames is one of the pillars of Gabor analysis. We establish a far-reaching generalization to Morita equivalence bimodules with some extra properties. For certain twisted group C∗-algebras, ... -
Groupoids and Hermitian Banach *-algebras
Ortega Esparza, Eduardo; Austad, Are (Peer reviewed; Journal article, 2022)We study when the twisted groupoid Banach ∗-algebra L 1 (G, σ) is Hermitian. In particular, we prove that Hermitian groupoids satisfy the weak containment property. Furthermore, we find that for L 1 (G, σ) to be Hermitian ... -
Heisenberg modules as function spaces
Enstad, Ulrik Bo Rufus; Austad, Are (Peer reviewed; Journal article, 2020)Let \Delta be a closed, cocompact subgroup of G \times \widehat{G}, where G is a second countable, locally compact abelian group. Using localization of Hilbert C^*-modules, we show that the Heisenberg module \mathcal ... -
Modulation spaces as a smooth structure in noncommutative geometry
Austad, Are; Luef, Franz (Peer reviewed; Journal article, 2021)We demonstrate how to construct spectral triples for twisted group C^*-algebras of lattices in phase space of a second-countable locally compact abelian group using a class of weights appearing in time–frequency analysis. ... -
Spectral Invariance of ∗ -Representations of Twisted Convolution Algebras with Applications in Gabor Analysis
Austad, Are (Journal article; Peer reviewed, 2021)We show spectral invariance for faithful ∗-representations for a class of twisted convolution algebras. More precisely, if G is a locally compact group with a continuous 2-cocycle c for which the corresponding Mackey group ... -
The Algebraic Bivariant Connes-Chern Character
Austad, Are (Master thesis, 2017)In this thesis we present many properties of bivariant periodic cyclic homology with the purpose of then constructing two bivariant Connes-Chern characters from algebraic versions of Kasparov's KK-theory with values in ... -
Twisted Convolution Algebras and Applications to Gabor Analysis
Austad, Are (Doctoral theses at NTNU;2021:155, Doctoral thesis, 2021)This thesis concerns several aspects of twisted convolution algebras, with a particular focus on problems arising in Gabor analysis. A significant portion of the thesis is dedicated to the study of Hilbert C -modules known ...