Top-level heading

Graph products, ε-independence, and atoms

Categoria
Altro (categoria non censita)
Categoria non censita
Operator Algebra Seminar in Tor Vergata
Data e ora inizio evento
Data e ora fine evento
Aula
Altro (Aula esterna al Dipartimento)
Sede

Dipartimento di Matematica, Università di Roma Tor Vergata

Aula esterna
Aula Dal Passo
Speaker
Ian Charlesworth (Cardiff University, School of Mathematics)
Abstract: In both classical and free probability theory, the central limit distribution can be modeled on a symmetric or free Fock space. The $q$-deformed Gaussians are the corresponding variables on a $q$-deformed Fock space (being the free semicirculars when $q = 0$ and the classical Gaussians when $q=1$), which raises the question of whether they arise from a central limit-type theorem. To find such a situation, Młotkowski introduced $\varepsilon$-independence as an interpolation between free and classical independence, where distributions (or von Neumann algebras) are assigned to the vertices of a graph with adjacency matrix $\varepsilon$, and are placed in a larger algebra in such a way that they are independent when they correspond to adjacent vertices and free otherwise. The corresponding product operation on von Neumann algebras corresponds to the idea of a graph product of groups, studied by Green. In this talk I will be interested in the following question: when do type I summands appear in the graph product of von Neumann algebras? The answer is pleasantly combinatorial, and can be described based on a family of polynomials built using the cliques in the graph (first arising in work of Cartier--Foata in 1969), and the behaviour of type I summands in the input algebras. This is joint work with David Jekel. Note: This talk is part of the activity of the MUR Excellence Department Project MatMod@TOV (CUP E83C23000330006) The Operator Algebra Seminar schedule is here: https://sites.google.com/view/oastorvergata/home-page