North Atlantic Noncommutative Geometry Seminar

June 11, 2025, 5:15 p.m.
GILLES GONÇALVES DE CASTRO (Universidade Federal de Santa Catarina, Florianópolis, Brazil)
TBA

June 4, 2025, 5:15 p.m.
ELIEZER BATISTA (Universidade Federal de Santa Catarina, Florianópolis, Brazil)
TBA

May 28, 2025, 5:15 p.m.
FABIO EUGENIO GIOVANNI CIPRIANI (Politecnico di Milano, Italy)
TBA

May 21, 2025, 5:15 p.m.
MARKUS B. FRÖB (Universität Leipzig, Germany)
NON-COMMUTATIVE COORDINATES FROM PERTURBATIVE QUANTUM GRAVITY (NON-COMMUTATIVE COORDINATES FROM PERTURBATIVE QUANTUM GRAVITY)
Local observables in (perturbative) quantum gravity are notoriously hard to define, since the gauge symmetry of gravity (diffeomorphisms) moves points on the manifold. In particular, this is a problem for backgrounds of high symmetry such …

May 14, 2025, 5:15 p.m.
PAWEL SARKOWICZ (University of Waterloo, Canada)
UNIVERSAL COVERING GROUPS OF UNITARY GROUPS (UNIVERSAL COVERING GROUPS OF UNITARY GROUPS)
We examine a notion from algebraic topology, that of "universal covering groups", with the goal of better understanding unitary groups of C*-algebras. We give a complete description of what these universal covering groups are for …

May 7, 2025, 5:15 p.m.
RUY EXEL (Universidade Federal de Santa Catarina, Florianópolis, Brazil)
FLOWS ON UNIFORM ROE ALGEBRAS (FLOWS ON UNIFORM ROE ALGEBRAS)
For a uniformly locally finite metric space (X,d), we investigate coarse flows on its uniform Roe algebra C*ᵤ(X), defined as one-parameter groups of automorphisms whose differentiable elements include all partial isometries arising from partial translations …

April 30, 2025, 5:15 p.m.
EUN JI KANG (Seoul National University, South Korea)
A CATEGORICAL INTERPRETATION OF CONTINUOUS ORBIT EQUIVALENCE FOR PARTIAL DYNAMICAL SYSTEMS (A CATEGORICAL INTERPRETATION OF CONTINUOUS ORBIT EQUIVALENCE FOR PARTIAL DYNAMICAL SYSTEMS)
We define the orbit morphism of partial dynamical systems, and prove that an orbit morphism being an isomorphism in the category of partial dynamical systems and orbit morphisms is equivalent to the existence of a …

April 23, 2025, 5:15 p.m.
ALCIDES BUSS (Universidade Federal de Santa Catarina, Florianópolis, Brazil)
AMENABILITY OF NON-HAUSDORFF ÉTALE GROUPOIDS AND NUCLEARITY OF THEIR C*-ALGEBRAS (AMENABILITY OF NON-HAUSDORFF ÉTALE GROUPOIDS AND NUCLEARITY OF THEIR C*-ALGEBRAS)
The link between amenability and nuclearity lies at the heart of many structural results in operator algebras. For discrete groups, these notions are famously equivalent via the reduced group C*-algebra. In this talk, I will …

April 16, 2025, 5:15 p.m.
ROBERTA ISEPPI (Georg-August-Universität Göttingen, Germany)
FIRST STEPS TOWARDS THE QUANTISATION OF THE SPECTRAL ACTION: THE BATALIN-VILKOVISKY CONSTRUCTION OF FINITE SPECTRAL TRIPLES (FIRST STEPS TOWARDS THE QUANTISATION OF THE SPECTRAL ACTION: THE BATALIN-VILKOVISKY CONSTRUCTION OF FINITE SPECTRAL TRIPLES)
The quantisation of the spectral action associated with spectral triples remains a largely open problem. Even within a perturbative framework, significant complications arise in the presence of non-abelian gauge symmetries. This is precisely where the …

April 9, 2025, 5:15 p.m.
IVÁN RUIZ CAMPOS (Universidad de Málaga, Spain)
ASSOCIATIVE COMMUTATIVE REPRESENTATIONS OF EVOLUTION ALGEBRAS IN DIMENSION TWO (ASSOCIATIVE COMMUTATIVE REPRESENTATIONS OF EVOLUTION ALGEBRAS IN DIMENSION TWO)
In this talk, we study the faithful associative commutative (unitary) representations of evolution algebras of dimension two. This analysis involves the computation of the (tight) p−algebra associated with any 2-dimensional evolution algebra, whenever it exists. …

April 2, 2025, 5:15 p.m.
MARIUSZ TOBOLSKI (Uniwersytet Wrocławski, Poland)
GLUING TOPOLOGICAL-GRAPH C*-ALGEBRAS (GLUING TOPOLOGICAL-GRAPH C*-ALGEBRAS)
Katsura's topological-graph C*-algebras generalize graph C*-algebras and homeomorphism C*-algebras. In this talk, I will present a class of topological-graph C*-algebras coming from noncommutative topology that are not graph C*-algebras, notably the C*-algebras of odd-dimensional Hong-Szymański …

March 26, 2025, 5:15 p.m.
ŁUKASZ KACZMARCZYK (Uniwersytet Warszawski, Poland)
INFORMATION GEOMETRY OF BAYESIAN UPDATING AND REPLICATION (INFORMATION GEOMETRY OF BAYESIAN UPDATING AND REPLICATION)
In this talk, I will show that the Kullback-Leibler divergence can be promoted to a functor from probabilistic spaces to convex polyhedra with a distinguished convex function. Both domain and codomain of this functor enjoy …

March 19, 2025, 5:15 p.m.
GÁBOR ETESI (Budapesti Műszaki és Gazdaságtudományi Egyetem, Hungary)
AN OPERATOR ALGEBRAIC CHARACTERIZATION OF THE VACUUM EINSTEIN EQUATION IN FOUR DIMENSIONS (AN OPERATOR ALGEBRAIC CHARACTERIZATION OF THE VACUUM EINSTEIN EQUATION IN FOUR DIMENSIONS)
In this talk, a new approach to the vacuum Einstein equation on four dimensional Riemannian manifolds (i.e. the Einstein condition on a four dimensional Riemannian metric) is offered in the framework of dynamical systems on …

March 12, 2025, 5:15 p.m.
JACOPO BASSI (MPAN, Warszawa, Poland)
ON ISOMETRIES FOR SPECTRAL TRIPLES ON AF ALGEBRAS (ON ISOMETRIES FOR SPECTRAL TRIPLES ON AF ALGEBRAS)
In this talk, I will discuss some results on the structure of natural non-commutative analogues of groups of isometries for the spectral triples on AF-algebras introduced by Christensen and Ivan. This is a joint work …

March 5, 2025, 5:15 p.m.
MARCELO LACA (University of Victoria, Canada)
A HIGH-TEMPERATURE PHASE TRANSITION FROM NUMBER THEORY (A HIGH-TEMPERATURE PHASE TRANSITION FROM NUMBER THEORY)
Let S be the semidirect product of the multiplicative positive integers acting on the integers, with the operation (a,m)(b,n) = (ab,bm+n), where a and b are positive. In previous joint work with Astrid an Huef …