| 01/04/26 | Colloquium | 16:00 | 17:00 | 1201 Dal Passo | Mikael Rørdam | University of Copenhagen |
Colloquium "Levi-Civita"
The Connes Embedding Problem, Kirchberg’s reformulations, Tsirelson’s conjecture, and MIP*=RE
In his seminal classification paper from 1976, Connes remarked that every separable tracial von Neumann algebra ought to be embeddable into an ultrapower of the hyperfinite type II_1 factor, or, in other words, be approximable by matrices. Over the following decades, the Connes Embedding Problem (CEP) remained unsolved, but many interesting and deep reformulations were discovered. Prominently, Kirchberg proved in his famous 1991 Inventiones paper that CEP is equivalent to several questions concerning C*-algebras and their tensor product, including his QWEP conjecture. He also showed that CEP holds if and only if there is a unique C*-norm of the tensor product of two copies of the full group C*-algebra of the free group. The latter was shown (by several authors) to be equivalent to Tsirelson’s conjecture about quantum correlations. CEP also relates to the open problems in group theory if all infinite discrete groups are sofic. Recently, Ji-Natarajan-Vidick-Wright-Yuen announced a negative solution to Tsirelson’s conjecture, and hence also a negative answer to CEP by proving that two complexity classes are the same |
| 24/03/26 | Seminario | 14:30 | 15:30 | 1201 Dal Passo | Daniele Struppa | Chapman University | Seminario di Equazioni Differenziali
Superoscillazioni: un ponta tra fisica, analisi e teoria dei numeri
Le superoscillazioni sono un fenomeno che nasce dalla teoria dei misuramenti deboli di Aharonov ma che trovano inaspettate applicazioni in microscopia (superrisoluzione) ed in teoria dei numeri. Da un punto di vista matematico danno origine ad un fenomeno, detto supershift, che imita il comportamento delle funzioni analitiche. La precisa relazione tra queste due nozioni è più complessa di quanto ci si possa aspettare. In questo seminario darò le nozioni di base sulle funzioni superoscillanti e discuterò brevemente le loro applicazioni alla microscopia e alla teoria dei numeri. Concluderò discutendo la nozione di supershift e la sua relazione con il concetto di analiticità.
NB:
This talk is part of the activity of the MUR Excellence Department Project MATH@TOV CUP E83C23000330006
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| 24/03/26 | Seminario | 14:30 | 16:00 | 1101 D'Antoni | Riccardo Salvati Manni | Università di Roma La Sapienza | Geometry Seminar
Slope of Siegel modular forms
I will study the Kodaira dimension of $A_6$, i.e., the moduli space of principally polarized Abelian $g$-folds, and of $X_g^n$, i.e., the space of Kuga $n$-fold varieties on these spaces. I will then use the results on the slope of Siegel modular forms to determine the Kodaira dimension for all Kuga varieties and $A_g (g
eq 6)$. I will report the results for the case $g=6$. If I have time, I will report the results on the moving slope of $A_g$. These results were obtained in collaboration with: Dittmann, Scheithauer, Poon, Sankaran, Grushevsky, Ibukiyama, and Mondello.
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 |
| 20/03/26 | Seminario | 16:00 | 17:00 | 1201 Dal Passo | Victor TURCHIN | Kansas State University |
Joint Topology & Algebra and Representation Theory Seminar (T-ARTS)
"Graph-complexes and rational homotopy theory of embedding spaces"
N.B.: this talk is part of the activity of the MIUR Excellence Department Project MatMod@TOV (CUP E83C23000330006)
The homotopy groups of CW complexes and of the mapping spaces between them are notoriously difficult to compute. However, if one disregards torsion, rational homotopy theory becomes very effective and can easily solve such problems. Moreover, it produces efficient invariants of homotopy classes of maps, called Maurer-Cartan elements, which encode the rational type of path components. I will give a couple of examples and then explain how this extends to embedding spaces.
Based on joint work with Benoit Fresse and Thomas Willwacher.
N.B.: this talk is part of the activity of the MIUR Excellence Department Project MatMod@TOV (CUP E83C23000330006)
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| 20/03/26 | Seminario | 14:30 | 15:30 | 1201 Dal Passo | Ben MILLS | York University |
Algebra & Representation Theory Seminar (ARTS)
"Utilising Meta Kazhdan-Lusztig Combinatorics"
N.B.: this talk is part of the activity of the MIUR Excellence Department Project MatMod@TOV (CUP E83C23000330006)
Parabolic Kazhdan-Lusztig polynomials are ubiquitous across representation theory, geometry, and Lie theory. This raises two questions: can the (often strictly combinatorial) methods used to compute them be enriched to shed light on algebraic and geometric structures? Furthermore, if two a priori distinct structures are governed by the same polynomials, does this imply a deeper equivalence? <br>
In this talk, we address these questions for parabolic Kazhdan-Lusztig polynomials of type (<em>D<sub>n</sub></em> , <em>A</em><sub><em>n</em>-1</sub>) . By enriching the combinatorial methods to calculate these polynomials, we give a new presentation of the structure for the basic algebra of the anti-spherical Hecke category of isotropic Grassmannians. We then use this enriched structure to prove that it is isomorphic to the type <em>D</em> Khovanov arc algebra.
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<em> <strong><u>N.B.</u>:</strong> this talk is part of the activity of the MIUR Excellence Department Project MatMod@TOV (CUP E83C23000330006) </em>
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| 18/03/26 | Seminario | 16:00 | 17:00 | 1201 Dal Passo | Robert Simon | London School of Economics and Political Science |
Operator Algebras Seminar
Paradoxical decompositions as the only solutions to locally finite conditions
Note:This talk is part of the activity of the MUR Excellence Department Project MatMod@TOV (CUP E83C23000330006)
Assuming g_1, g_2, ..., g_k are measure preserving transformations on a probability space X, we require that a function f from X to a measurable space Y satisfies that f(x) is in F(x, f(g_1 x), .... f(g_k x) ) almost everywhere for an upper semi continuous correspondence F defined on X x Y^k. If there exists such functions however NONE of them are measurable with respect to any finitely additive extension of the probability measure for which the g_i are still measure preserving, we say that the correspondence F is paradoxical. We demonstrate some paradoxical correspondences that are also convex valued and nowhere empty. We are curious if there are applications beyond optimization and economics. |
| 17/03/26 | Seminario | 16:00 | 17:00 | 1201 Dal Passo | Fabrizio Bianchi | Università di Pisa | Seminario di Sistemi Dinamici
Dynamics of Hénon-like maps
Hénon-like maps are invertible holomorphic maps, defined on some convex bounded domain of $mathbb C^k$, that have (non-uniform) expanding behaviour in $p$ directions and contracting behaviour in the remaining $k-p$ directions. They form a large class of dynamical systems in any dimension. In dimension 2, they contain the Hénon maps, which are among the most studied dynamical systems. In this talk, I will give an overview of the main dynamical properties of these maps. In particular, I will focus on how tools from pluripotential theory can allow one to go beyond the algebraic setting of the Hénon maps. The talk is based on joint works with Tien-Cuong Dinh and Karim Rakhimov.
Note:
This talk is part of the activity of the MIUR Department of Excellence Project MatMod@TOV (2023-2027) |
| 17/03/26 | Seminario | 14:30 | 15:30 | 1201 Dal Passo | Corentin Fierobe | Università di Roma | Seminario di Sistemi Dinamici
One Can Hear Symmetric Billiard Tables Close to Ellipses
This talk addresses Kac’s famous question, “Can one hear the shape of a drum?”—that is, whether the spectrum of the Laplacian on a domain uniquely determines its shape— in the context of convex planar billiard tables. While non-convex counterexamples are known (Gordon–Webb–Wolpert), the problem remains open for strictly convex domains with smooth boundaries. As shown by Anderson, Melrose, and Guillemin, the spectral question is deeply connected to its dynamical analogue: whether the length spectrum—the set of lengths of all periodic billiard trajectories—determines the domain up to isometry. In joint work with Vadim Kaloshin and Alfonso Sorrentino, we show that this is indeed the case for domains that are sufficiently close to a general ellipse and possess dihedral symmetry.
Note: This talk is part of the activity of the MIUR Department of Excellence Project MatMod@TOV (2023–2027). |
| 10/03/26 | Seminario | 14:30 | 15:30 | 1201 Dal Passo | Nicola Picenni | Università di Pisa | Seminario di Equazioni Differenziali
A notion of fractional area in codimension 2
We consider a notion of fractional s-area for codimension 2 surfaces in a closed Riemannian manifold or the Euclidean space, which can be seen as an extension of the fractional perimeter to higher codimension. The definition involves a minimum problem over a class of circle-valued maps having prescribed singularities on the given surface.
We discuss various properties of the s-area when s is fixed, and we show that when s tends to 1 it Gamma-converges, with coercivity, to the classical area in the framework of currents.
The talk is based on a joint project with Michele Caselli and Mattia Freguglia.
Note: This talk is part of the activity of the MIUR Department of Excellence Project MatMod@TOV (2023–2027). |
| 10/03/26 | Seminario | 14:30 | 16:00 | 1101 D'Antoni | Angelica Cueto | Ohio State University | Geometry Seminar
Tritangent planes to space sextic curves: a tropical viewpoint
A classical result due to Clebsch from the mid-nineteenth century confirms that every complex space sextic curve (given as an intersection of a quadric and a cubic surface in projective 3-space) has exactly 120 tritangent planes. In this talk we will show how to use combinatorial methods arising from tropical geometry to revisit this classical problem and perform the analogous count over the reals and extensions thereof. This is joint work with Yoav Len, Hannah Markwig and Yue Ren (arXiv:2512.24277).
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 |