16 citations · 125 across the 34 of their papers we have counts for
15 papers · 1 filter
Twisted tensor products of field algebras
Ezio Vasselli
Let A be a C*-algebra, h a Hilbert space and C the CAR algebra over h. We construct a twisted tensor product of A by C such that the two factors are not necessarily one in the rela…
Gerbes over posets and twisted C*-dynamical systems
Ezio Vasselli
A base generating the topology of a space becomes a partially ordered set (poset), when ordered under inclusion of open subsets. Given a precosheaf over of fixed-point…
The C(X)-algebra of a net and index theory
Giuseppe Ruzzi, Ezio Vasselli
Given a connected and locally compact Hausdorff space X with a good base K we assign, in a functorial way, a C(X)-algebra to any precosheaf of C*-algebras A defined over K. Afterwa…
A new light on nets of C*-algebras and their representations
Giuseppe Ruzzi, Ezio Vasselli
The present paper deals with the question of representability of nets of C*-algebras whose underlying poset, indexing the net, is not upward directed. A particular class of nets, c…
Bundles of C*-categories, II: C*-dynamical systems and Dixmier-Douady invariants
Ezio Vasselli
We introduce a cohomological invariant arising from a class in nonabelian cohomology. This invariant generalizes the Dixmier-Douady class and encodes the obstruction to a C*-algebr…
Extension of automorphisms to C*-crossed products with non-trivial centre
Roberto Conti, Ezio Vasselli
Given a quasi-special endomorphism of a C*-algebra A with nontrivial center, we study an extension problem for automorphisms of A to a minimal cross-product B of A by . Expl…
Gauge-equivariant Hilbert bimodules and crossed products by endomorphisms
Ezio Vasselli
C*-endomorphisms arising from superselection structures with non-trivial centre define a 'rank' and a 'first Chern class'. Crossed products by such endomorphisms involve the Cuntz-…
Realization of minimal C*-dynamical systems in terms of Cuntz-Pimsner algebras
Fernando Lledó, Ezio Vasselli
In the present paper we study tensor C*-categories with non-simple unit realised as C*-dynamical systems (F,G,β) with a compact (non-Abelian) group G and fixed point algebra A := F…
On the nuclearity of certain Cuntz-Pimsner algebras
Fernando Lledó, Ezio Vasselli
We give a short proof of the nuclearity property of a class of Cuntz-Pimsner algebras associated with a Hilbert A-bimodule M, where A is a separable and nuclear C*-algebra. We assu…
Crossed products by endomorphisms, vector bundles and group duality, II
Ezio Vasselli
We study C*-algebra endomorphims which are special in a weaker sense w.r.t. the notion introduced by Doplicher and Roberts. We assign to such endomorphisms a geometrical invariant,…
The C*-algebra of a vector bundle and fields of Cuntz algebras
Ezio Vasselli
We study the Pimsner algebra associated with the module of continuous sections of a Hilbert bundle, and prove that it is a continuous bundle of Cuntz algebras. We discuss the role…
Crossed Products by Endomorphisms, Vector Bundles and Group Duality
Ezio Vasselli
We construct the crossed product of a C(X)-algebra by an endomorphism, in such a way that the endomorphism itself becomes induced by the bimodule of continuous sections of a vector…
Some Remarks on Group Bundles and C*-dynamical systems
Ezio Vasselli
We introduce the notion of fibred action of a group bundle on a C(X)-algebra. By using such a notion, a characterization in terms of induced C*-bundles is given for C*-dynamical sy…
Crossed products of C(X)-algebras by endomorphisms and C(X)-categories
Ezio Vasselli
We construct the crossed product of a C(X)-algebra by an endomorphism, in such a way that it becomes induced by a Hilbert C(X)-bimodule. Furthermore we introduce the notion of C(X)…
Continuous Fields of -Algebras Arising from Extensions of Tensor -Categories
Ezio Vasselli
The notion of extension of a given -category by a -algebra is introduced. In the commutative case , the objects of the extension category are interprete…