Dipartimento di Matematica -UTV-

Date	Type	Start	End	Room	Speaker	From	Title
03/02/26	Seminario	14:30	16:00	1101 D'Antoni	Tim Browning	IST Austria	Geometry Seminar Pairs of commuting matrices Abstract I'll discuss commuting varieties and a new upper bound for the density of pairs of commuting n x n matrices with integer entries. Our approach uses Fourier analysis and reduction modulo a suitably chosen prime, together with a result about the flatness of the commutator Lie bracket, which we also solve. This is joint work with Will Sawin and Victor Wang. <em> Note: </em> This talk is part of the activity of the MIUR Department of Excellence Project MatMod@TOV (2023-2027) and the PRIN 2022 Moduli Spaces and Birational Geometry and Prin PNRR 2022 Mathematical Primitives for Post Quantum Digital Signatures
20/01/26	Seminario	14:30	16:00	1101 D'Antoni	Madhavan Venkatesh	(MPI Saarbrücken)	Geometry Seminar Counting points on surfaces Abstract I will present a randomised algorithm to compute the local zeta function of a fixed smooth, projective surface over the rationals, at any large prime p of good reduction. The runtime of the algorithm is polynomial in log p, answering a question of Couveignes and Edixhoven. The main ingredient is to explicitly compute cocycles associated to a Lefschetz pencil on the surface. This is based on joint work with Nitin Saxena. Note: This talk is part of the activity of the MIUR Department of Excellence Project MatMod@TOV (2023-2027) and the PRIN 2022 Moduli Spaces and Birational Geometry and Prin PNRR 2022 Mathematical Primitives for Post Quantum Digital Signatures
15/01/26	Seminario	14:30	15:30	1101 D'Antoni	Espen Sande	Simula Research Laboratory, Oslo	On a robust inf-sup condition for the Stokes problem in slender domains – with application to preconditioning Abstract We identify a norm on the pressure variable in the Stokes equation that allows us to prove a continuous inf-sup condition with a constant independent of the domain's aspect ratio. This is in contrast to the standard inf-sup constant, which breaks down as the aspect ratio increases. We further apply our result to construct robust operator preconditioners for the Stokes problem in slender domains. Several numerical examples illustrate the theory. The talk is part of the activity of the MUR Excellence Department Project MatMod@TOV (CUP E83C23000330006).
14/01/26	Seminario	16:15	17:15	1201 Dal Passo	Giulio Tiozzo	Sapienza, Università di Roma	Seminario "Vito Volterra" On the singularity conjecture for random walks on groups Abstract Given a random walk on a group of isometries of hyperbolic (or other symmetric) space, one can consider its hitting measure, i.e. the probability that the walk converges to a given subset of the boundary. It has been discussed for several decades, starting with the work of Furstenberg in the late 60's, whether the hitting measure for a random walk can lie in the same measure class as a "nice" geometric measure, e.g. the Lebesgue measure on the boundary. It is a long-standing conjecture, formalized by Kaimanovich-Le Prince, that, if the group of isometries is discrete and the random walk is finitely supported, the hitting measure is always singular with respect to Lebesgue. We will explore this problem in various contexts, and discuss the state of the art and recent progress, based on joint works with N. Bogachev, P. Kosenko, H. Lee, and W. van Limbeek.
13/01/26	Seminario	14:30	16:00	1101 D'Antoni	Fabio Bernasconi	La Sapienza Università di Roma	Geometry Seminar Equisingular lifting of semi-log canonical F-split K-trivial surfaces Abstract The Bogomolov–Tian–Todorov (BTT) theorem states that smooth Calabi–Yau (CY) varieties over the complex numbers have unobstructed deformation spaces. While this fails over fields of positive characteristic, recent results of Brantner–Taelman and Petrov show that the BTT theorem does hold in positive and mixed characteristics for ordinary CY varieties without crystalline torsion, implying that such varieties are liftable. In this talk, we study the problem of liftability for singular CY surfaces over the ring of Witt vectors W(k). In earlier joint work with Brivio–Kawakami–Witaszek, we proved that normal globally $F$-split CY surfaces admit an equisingular lifting over W(k). Together with Q. Posva, building on the explicit birational geometry and the deformation theory of log CY surfaces, we further generalised this result to the case of globally $F$-split surfaces with semi-log canonical (in particular, not necessarily normal) singularities. In the first part, I will recall the setup and definitions in positive characteristic algebraic geometry, giving an overview of the proofs of some of the previous results. In the second part, I will focus on joint work with Posva and highlight the difficulties that arise in the non-normal case. Note: This talk is part of the activity of the MIUR Department of Excellence Project MatMod@TOV (2023-2027) and the PRIN 2022 Moduli Spaces and Birational Geometry and Prin PNRR 2022 Mathematical Primitives for Post Quantum Digital Signatures
09/01/26	Seminario	16:00	17:00	1201 Dal Passo	Francesco MEAZZINI	"Sapienza" Università di Roma	Algebra & Representation Theory Seminar (ARTS) "Deformations of monomial ideals" N.B.: this talk is part of the activity of the MIUR Excellence Department Project Mat-Mod@TOV (CUP E83C23000330006) Abstract We deal with infinitesimal deformations of affine schemes defined by a monomial ideal in a polynomial ring. We discuss a few applications: the cotangent cohomology for Stanley-Reisner schemes, some conjectures related to fat points, and some geometric properties of certain Hilbert schemes of points. This is a joint work (partially in progress) with Nathan Ilten and Andrea Petracci. N.B.: this talk is part of the activity of the MIUR Excellence Department Project MatMod@TOV (CUP E83C23000330006)
09/01/26	Seminario	14:30	15:30	1201 Dal Passo	Marvin DIPPELL	Universität Köln	Algebra & Representation Theory Seminar (ARTS) "Deformation theory of constraint algebras" N.B.: this talk is part of the activity of the MIUR Excellence Department Project Mat-Mod@TOV (CUP E83C23000330006) Abstract After an introduction to (formal) deformation quantization of Poisson manifold, focusing on the deformation theory of associative algebras following Gerstenhaber, I will introduce constraint algebras as a way to study (symmetry) reduction in this setting. Constraint algebras encode the additional structure on the algebra of functions on a manifold needed for reduction and their deformations yield (formal) quantizations compatible with reduction. I will discuss the deformation theory of these constraint algebras and present some results about an adapted Hochschild-Kostant-Rosenberg Theorem computing the cohomology controlling this deformation theory. N.B.: this talk is part of the activity of the MIUR Excellence Department Project MatMod@TOV (CUP E83C23000330006)
18/12/25	Seminario	16:00	17:00	1201 Dal Passo	Pierre Bieliavsky	UC Louvain	Operator Algebras Seminar The space of star-products of a homogeneous symplectic manifold Note:This talk is part of the activity of the MUR Excellence Department Project MatMod@TOV (CUP E83C23000330006) Abstract
17/12/25	Seminario	17:10	18:10	1201 Dal Passo	Fabio Cipriani	Politecnico di Milano	Operator Algebras Seminar Existence of ground states of Hamiltonians satisfying energy-entropy inequalities Note:This talk is part of the activity of the MUR Excellence Department Project MatMod@TOV (CUP E83C23000330006) Abstract
17/12/25	Seminario	16:00	17:00	1201 Dal Passo	Edoardo D'Angelo	Università di Milano	Operator Algebras Seminar A locally covariant renormalization group in Lorentzian spacetimes Note:This talk is part of the activity of the MUR Excellence Department Project MatMod@TOV (CUP E83C23000330006) Abstract Renormalization group flows, based on functional Polchinski or Wetterich equations, are powerful tools that give access to non-perturbative aspects of strongly coupled QFTs and gravity. I will provide an overview of a new approach, developed to construct a rigorous renormalization group (RG) flow on Lorentzian manifolds. This approach, based on a local and covariant regularization of the Wetterich equation, highlights its state dependence. I give the main ideas of a proof of local existence of solutions for the RG equation, when a suitable Local Potential Approximation is considered. The proof is based on an application of the renown Nash-Moser theorem. I will also present recent applications of the locally covariant RG equation to the non-perturbative renormalizability of quantum gravity.