46 citations · 126 across the 15 of their papers we have counts for
16 papers
Piecewise principal comodule algebras
Piotr M. Hajac, Ulrich Kraehmer, Rainer Matthes +1
A comodule algebra P over a Hopf algebra H with bijective antipode is called principal if the coaction of H is Galois and P is H-equivariantly projective (faithfully flat) over the…
Index pairings for pullbacks of C*-algebras
L. Dabrowski, T. Hadfield, P. M. Hajac +2
In this overview, we study how to reduce the index pairing for a fibre-product C*-algebra to the index pairing for the C*-algebra over which the fibre product is taken. As an examp…
Noncommutative Geometry Approach to Principal and Associated Bundles
Paul F. Baum, Piotr M. Hajac, Rainer Matthes +1
We recast basic topological concepts underlying differential geometry using the language and tools of noncommutative geometry. This way we characterize principal (free and proper)…
Noncommutative index theory for mirror quantum spheres
Piotr M. Hajac, Rainer Matthes, Wojciech Szymanski
We introduce and analyse a new type of quantum 2-spheres. Then we apply index theory for noncommutative line bundles over these spheres to conclude that quantum lens spaces are non…
The K-Theory of Heegaard-Type Quantum 3-Spheres
Paul Baum, Piotr M. Hajac, Rainer Matthes +1
We use a Heegaard splitting of the topological 3-sphere as a guiding principle to construct a family of its noncommutative deformations. The main technical point is an identificati…
Chern numbers for two families of noncommutative Hopf fibrations
Piotr M. Hajac, Rainer Matthes, Wojciech Szymanski
We consider noncommutative line bundles associated with the Hopf fibrations of SUq(2) over all Podles spheres and with a locally trivial Hopf fibration of S^3_{pq}. These bundles a…