North Atlantic Noncommutative Geometry Seminar

March 18, 2026, 5:15 p.m.
EVA-MARIA HEKKELMAN (Max-Planck-Institut für Mathematik, Bonn, Germany)
UNBOUNDED OPERATOR INTEGRALS AND NONCOMMUTATIVE QUANTUM FIELD THEORY (UNBOUNDED OPERATOR INTEGRALS AND NONCOMMUTATIVE QUANTUM FIELD THEORY)
In Noncommutative Geometry, operator integrals appear in abundance. However, since the involved operator arguments are typically unbounded, they do not neatly fit the usual theories of Multiple Operator Integrals (MOIs). To solve this problem, in …

March 11, 2026, 5:15 p.m.
DIMITRIS M. GERONTOGIANNIS (IMPAN, Warszawa, Poland)
QUANTUM ISOMETRY GROUPS OF LOG-LAPLACIANS ON CUNTZ-KRIEGER ALGEBRAS (QUANTUM ISOMETRY GROUPS OF LOG-LAPLACIANS ON CUNTZ-KRIEGER ALGEBRAS)
In recent work with Magnus Goffeng and Bram Mesland, we showed that Cuntz-Krieger algebras admit canonical spectral triples via the log-Laplacian. This talk concerns the quantum symmetries preserving this differential structure. They lead to a …

March 4, 2026, 5:15 p.m.
STEFAN WAGNER (Blekinge Tekniska Högskola, Karlskrona, Sweden)
NONCOMMUTATIVE PRINCIPAL BUNDLES AND CENTRAL EXTENSIONS (NONCOMMUTATIVE PRINCIPAL BUNDLES AND CENTRAL EXTENSIONS)
In Riemannian geometry, spin structures arise from lifting frame bundles along the universal covering of the structure group, with the existence and classification governed by cohomological obstructions. In this talk, I will present a noncommutative …

Feb. 25, 2026, 5:15 p.m.
NATÃ MACHADO (Universidade Federal de Santa Catarina, Florianópolis, Brazil)
CLASSIFICATION OF SATURATED FELL BUNDLES: THE DISCRETE CASE AND BEYOND (CLASSIFICATION OF SATURATED FELL BUNDLES: THE DISCRETE CASE AND BEYOND)
Using data associated with the base group and the unit fiber, we present a classification framework for saturated Fell bundles over groups. In the case of discrete groups, this classification is given in terms of …

Jan. 21, 2026, 5:15 p.m.
FABIO GAVARINI (Università di Roma Tor Vergata, Italy)
MULTIPARAMETER QUANTUM GROUPS, DEFORMATIONS AND SPECIALISATIONS (MULTIPARAMETER QUANTUM GROUPS, DEFORMATIONS AND SPECIALISATIONS)
We introduce the notion of a formal multiparameter quantum universal enveloping algebra (FoMpQUEA) as a straightforward generalization of Drinfeld’s quantum group Uℏ(g), where the underlying Lie algebra g is any symmetrizable Kac-Moody algebra. Then we …

Jan. 14, 2026, 5:15 p.m.
TOMASZ MASZCZYK (Uniwersytet Warszawski, Poland)
The Leavitt Path Algebras of Quantum Quivers (The Leavitt Path Algebras of Quantum Quivers)
We introduce a topos of quantum sets and study the properties of the embedding of the classical topos of sets in it. In this way, we derive the Birkhoff-von Neumann quantum logic and many other …

Jan. 7, 2026, 5:15 p.m.
PIOTR M. HAJAC (IMPAN, Warszawa, Poland)
COMPUTING ASSOCIATED PROJECTIVE MODULES USING THE MILNOR CLUTCHING (COMPUTING ASSOCIATED PROJECTIVE MODULES USING THE MILNOR CLUTCHING)
Principal bundles can be viewed as strongly monoidal functors from the finite-dimensional representation category of a structure group to the category of associated vector bundles. Much in the same way, principal comodule algebras can be …

Dec. 17, 2025, 5:15 p.m.
FRÉDÉRIC LATRÉMOLIÈRE (University of Denver, USA)
A GROMOV-HAUSDORFF HYPERTOPOLOGY OVER THE CLASS OF PROPER QUANTUM METRIC SPACES (A GROMOV-HAUSDORFF HYPERTOPOLOGY OVER THE CLASS OF PROPER QUANTUM METRIC SPACES)
The field of noncommutative metric geometry has grown to provide a framework for the convergence, à la Gromov, of compact quantum metric spaces and various associated structures. However, the question of extending this theory to …

Dec. 10, 2025, 5:15 p.m.
ALONSO DELFIN (University of Colorado, Boulder, USA)
TWISTED CROSSED PRODUCTS OF BANACH ALGEBRAS (TWISTED CROSSED PRODUCTS OF BANACH ALGEBRAS)
The main goal of this talk is to introduce twisted crossed products of Banach algebras by locally compact groups. Classical crossed products of Banach algebras have been extensively studied for different classes of representations, including …

Dec. 3, 2025, 5:15 p.m.
YAN SOIBELMAN (Kansas State University, Manhattan, USA)
RIEMANN-HILBERT CORRESPONDENCE FROM THE POINT OF VIEW OF HOLOMORPHIC FLOER THEORY (RIEMANN-HILBERT CORRESPONDENCE FROM THE POINT OF VIEW OF HOLOMORPHIC FLOER THEORY)
To a complex symplectic manifold M one can assign two non-commutative spaces represented by two categories: one by the category of modules over the quantized sheaf of analytic functions on M, and one by the …

Nov. 26, 2025, 5:15 p.m.
WALTER VAN SUIJLEKOM (Radboud Universiteit, Nijmegen, The Netherlands)
A GENERALIZATION OF K-THEORY TO OPERATOR SYSTEMS (A GENERALIZATION OF K-THEORY TO OPERATOR SYSTEMS)
We propose a generalization of K-theory to operator systems. Motivated by spectral truncations of noncommutative spaces described by C*-algebras, and inspired by the realization of the K-theory of a C*-algebra as the Witt group of …

Nov. 19, 2025, 5:15 p.m.
KULUMANI M. RANGASWAMY (University of Colorado, Colorado Springs, USA)
NAIMARK'S PROBLEM FOR GRAPH C*-ALGEBRAS AND LEAVITT PATH ALGEBRAS (NAIMARK'S PROBLEM FOR GRAPH C*-ALGEBRAS AND LEAVITT PATH ALGEBRAS)
Naimark's problem asks whether a C*-algebra having a unique irreducible *-representation up to unitary equivalence is isomorphic to the C*-algebra of compact operators on some (not necessarily separable) Hilbert space. Here, we consider Naimark's problem …

Nov. 12, 2025, 5:15 p.m.
JENS KAAD (Syddansk Universitet, Odense, Denmark)
SPECTRAL LOCALIZERS IN KK-THEORY (SPECTRAL LOCALIZERS IN KK-THEORY)
In this talk, we compute the index homomorphism of even K-groups arising from a class in even KK-theory via the Kasparov product. Due to the seminal work of Baaj and Julg, under mild conditions on …

Nov. 5, 2025, 5:15 p.m.
MARIUSZ TOBOLSKI (Uniwersytet Wrocławski, Wrocław, Poland)
LOCALLY DERIVED GRAPHS (LOCALLY DERIVED GRAPHS)
Voltage and derived graphs (also called base and skew product graphs, respectively) were introduced by Gross and Tucker to study free actions of groups on graphs. These notions found applications in the theory of C*-algebras …

Oct. 29, 2025, 5:15 p.m.
ZACHARY MESYAN (University of Colorado, Colorado Springs, USA)
POSETS FROM LEAVITT PATH ALGEBRAS AND GRAPH INVERSE SEMIGROUPS (POSETS FROM LEAVITT PATH ALGEBRAS AND GRAPH INVERSE SEMIGROUPS)
We discuss parallel developments in the study of three types of well-known algebraic objects built from directed graphs: Leavitt path algebras, graph inverse semigroups, and graph C*-algebras. Similar results have been proved about those objects, …