activity
20062026
most citedRieffel deformation via crossed products

45 citations · 139 across the 19 of their papers we have counts for

collaborators

33 papers

math.OA2026

Laplace operators on quantum graphs

Arkadiusz Bochniak, Dawid Jasiński, Paweł Kasprzak

We introduce a class of Laplace operators associated with quantum graphs in the operator-system framework. To this end, we investigate structural properties of quantum graphs relat…

math.OA2025

Quantum Mycielskians: symmetries, twin vertices and distinguishing labelings

Arkadiusz Bochniak, Igor Chełstowski, Paweł Kasprzak +1

We investigate a quantum generalization of the Mycielski construction for quantum graphs. In particular, we analyze the quantum symmetries of quantum Mycielskians and their relatio…

math.OA2021

Quantum correlations on quantum spaces

Arkadiusz Bochniak, Paweł Kasprzak, Piotr M. Sołtan

For given quantum (non-commutative) spaces and we study the quantum space of maps from to .…

physics.data-an2020

Resolution Enhancement in Protein NMR Spectra by Deconvolution with Compressed Sensing Reconstruction

Krzysztof Kazimierczuk, Paweł Kasprzak, Panagiota S. Georgoulia +6

Multidimensional NMR spectroscopy is one of the basic tools for determining the structure of biomolecules. Unfortunately, the resolution of the spectra is often limited by inter-nu…

math.OA2020★ 15 cited

Noncommutative Furstenberg boundary

Mehrdad Kalantar, Paweł Kasprzak, Adam Skalski +1

We introduce and study the notions of boundary actions and of the Furstenberg boundary of a discrete quantum group. As for classical groups, properties of boundary actions turn out…

math.OA2019

Kawada-Itô-Kelley Theorem for Quantum Semigroups

Paweł Kasprzak, Fatemeh Khosravi, Piotr M. Sołtan

Idempotent states on locally compact quantum semigroups with weak cancellation properties are shown to be Haar states on a certain sub-object described by an operator system with c…

math.QA2018★ 3 cited

Generalized (co)integrals on coideal subalgebras

Paweł Kasprzak

Given a a Hopf algebra , its left coideal subalgebra and a non-zero multiplicative functional on , we define the space of left -integrals . We obse…

math.QA2018

Integrals in left coideal subalgebras and group-like projections

Alexandru Chirvasitu, Pawel Kasprzak, Piotr Szulim

We develop a theory of right group-like projections in Hopf algebras linking them with the theory of left coideal subalgebras with two sided counital integrals. Every right group-l…

math.OA2018

Shifts of group-like projections and contractive idempotent functionals for locally compact quantum groups

Paweł Kasprzak

A one to one correspondence between shifts of group-like projections on a locally compact quantum group which are preserved by the scaling group and contractive idem…

math.OA2018

The Lattice of Idempotent States on a Locally Compact Quantum Group

Paweł Kasprzak, Piotr M. Sołtan

We study lattice operations on the set of idempotent states on a locally compact quantum group corresponding to the operations of intersection of compact subgroups and forming the…

math.OA2017

Group-like projections for locally compact quantum groups

Ramin Faal, Paweł Kasprzak

Let be a locally compact quantum group. We give a 1-1 correspondence between group-like projections in preserved by the scaling group and idempo…

math.OA2017★ 6 cited

Induction for locally compact quantum groups revisited

Mehrdad Kalantar, Paweł Kasprzak, Adam Skalski +1

In this paper we revisit the theory of induced representations in the setting of locally compact quantum groups. In the case of induction from open quantum subgroups, we show that…

math.OA2016★ 1 cited

Quantum actions on discrete quantum spaces and a generalization of Clifford's theory of representations

Kenny De Commer, Paweł Kasprzak, Adam Skalski +1

To any action of a compact quantum group on a von Neumann algebra which is a direct sum of factors we associate an equivalence relation corresponding to the partition of a space in…

math.OA2016

Hopf images in locally compact quantum groups

Paweł Józiak, Paweł Kasprzak, Piotr M. Sołtan

This manuscript is devoted to the study of the concept of a generating subset (a.k.a. Hopf image of a morphism) in the setting of locally compact quantum groups. The aim of this pa…

math.QA2016

Fundamental isomorphism theorems for quantum groups

Alexandru Chirvasitu, Souleiman Omar Hoche, Paweł Kasprzak

The lattice of subgroups of a group is the subject of numerous results revolving around the central theme of decomposing the group into "chunks" (subquotients) that can then be com…

math.OA2016

Coideals, quantum subgroups and idempotent states

Pawel Kasprzak, Fatemeh Khosravi

We establish a one to one correspondence between idempotent states on a locally compact quantum group G and integrable coideals in the von Neumann algebra of bounded measurable fun…

math.OA2016

Integrable actions and quantum subgroups

Paweł Kasprzak, Fatemeh Khosravi, Piotr M. Sołtan

We study homomorphisms of locally compact quantum groups from the point of view of integrability of the associated action. For a given homomorphism of quantum groups $Π\colon\mathb…

math.QA2015

On the Hopf (co)center of a Hopf algebra

Alexandru Chirvasitu, Paweł Kasprzak

The notion of Hopf center and Hopf cocenter of a Hopf algebra is investigated by the extension theory of Hopf algebras. We prove that each of them yields an exact sequence of Hopf…

math.OA2015

Open quantum subgroups of locally compact quantum groups

Mehrdad Kalantar, Paweł Kasprzak, Adam Skalski

The notion of an open quantum subgroup of a locally compact quantum group is introduced and given several equivalent characterizations in terms of group-like projections, inclusion…

math.OA2015

The canonical central exact sequence for locally compact quantum groups

Paweł Kasprzak, Adam Skalski, Piotr M. Sołtan

For a locally compact quantum group we define its center, , and its quantum group of inner automorphisms, . We show…

math.OA2015

Quantum families of quantum group homomorphisms

Mariusz Budziński, Paweł Kasprzak

The notion of a quantum family of maps has been introduced in the framework of C*-algebras. As in the classical case, one may consider a quantum family of maps preserving additiona…

math.OA2014★ 6 cited

Quantum groups with projection and extensions of locally compact quantum groups

P. Kasprzak, P. M. Sołtan

The main result of the paper is the characterization of those locally compact quantum groups with projection, i.e. non-commutative analogs of semidirect products, which are extensi…

math.OA2014★ 16 cited

Braided quantum SU(2) groups

Paweł Kasprzak, Ralf Meyer, Sutanu Roy +1

We construct a family of q-deformations of SU(2) for complex parameters q not equal to 0. For real q, the deformation coincides with Woronowicz' compact quantum SU_q(2) group. For…

math.OA2014★ 5 cited

Quantum automorphism groups of finite quantum groups are classical

Paweł Kasprzak, Piotr M. Sołtan, Stanisław L. Woronowicz

In a recent paper of Bhowmick, Skalski and Sołtan the notion of a quantum group of automorphisms of a finite quantum group was introduced and, for a given finite quantum group G, e…