Notiziario Scientifico
a cura del Dipartimento di Matematica Guido Castelnuovo, Sapienza Università di Roma
Settimana dal 07-06-2021 al 13-06-2021
Lunedì 07 giugno 2021
Ore 14:30, https://meet.google.com/nie-attq-ged, Dipartimento di Matematica, Sapienza Università di Roma
Seminario di Analisi Matematica
Pieralberto Sicbaldi (Granada)
Existence and regularity of Faber-Krahn minimizers in a Riemannian manifold
We consider the problem of finding domains that minimize the
first eigenvalue of the Dirichlet Laplacian in a Riemannian manifold
under volume constraint (Faber-Krahn minimizers). In the Euclidean
setting such domains are balls, and existence and regularity of such
domains is trivial. In a non-Euclidean setting very few examples are
known. In this talk we will show a general result of existence and
regularity of Faber-Krahn minimizers, inspired by the analogous result
of existence and regularity of the solutions of the isoperimetric
problems in a Riemannian manifold. In particular we will show that
Faber-Krahn minimizers are regular in low dimension, and that there
exists a critical dimension after which they can have singularities.
Such critical dimension is related to the Alf-Caffarelli cone. This is a
joint work with J. Lamboley.
Martedì 08 giugno 2021
Ore 10:30, online, Dipartimento di Scienze di Base e Applicate per l'Ingegneria, Sapienza Università di Roma
Workshop
Diffusion in inhomogeneous and irregular environments
Online Event of the Research Unit of INdAM at Dept. Scienze di Base e Applicate per l'Ingegneria Sapienza Roma, Italy June 8, 2021 https://sites.google.com/uniroma1.it/workshop-on-diffusion. Free registration required; all activities will be online. Funded by INdAM. Speakers: prof. Adrian Muntean (Karlstad University, Sweden) prof. Alexander Nazarov (St. Petersburg State University, Russia) Problems of diffusion set in environments with irregularities, obstacles and in general not homogeneous are important both in theoretical and in applied mathematics. The literature on these topics is huge. In addition, they are among the main targets of the scientific interest of the INdAM Research Unit at our Department. Each one of the two speakers will give two seminars (one in the morning and one in the afternoon) introducing a subject in which he is an internationally known expert. The character of the seminars will be aimed at an audience with only a general knowledge of partial differential equations, functional analysis and their applications to diffusion. Specifically they will be of interest to PhD students of PhD programs in Mathematics, Physics, Applied Mathematics, Engineering. All the activities of the Workshop will be online. Please register at the site indicated above to receive updates and the link to the online conferences. The organizers D.Andreucci R.Capitanelli M.R.Lancia.
Martedì 08 giugno 2021
Ore 14:15, https://zoom.us/j/95624873567?pwd=V2QyQk1YaGtxb3ZxYVluMll0K1kyZz09, Dipartimento di Matematica, Sapienza Università di Roma
Seminario di Modellistica Differenziale Numerica
Francisco J. Silva (Università di Limoges (Francia))
Mean field games, fifth lesson.
In this lesson we continue with the study of first order MFGs. We will present an approximation of first order MFGs, in the so-called Lagrangian formulation, by a finite state and discrete time MFG. We will discuss in detail the construction of the scheme and we will present a convergence analysis as well as the fictitious play method, which is useful in order to solve the approximated MFG system.
Per informazioni, rivolgersi a: carlini@mat.uniroma1.it
Mercoledì 09 giugno 2021
Ore 14:00, Seminario telematico via Google Meet all'URL http://meet.google.com/jjt-toji-skw, Dipartimento di Matematica, Sapienza Università di Roma
Seminario di Algebra e Geometria
Jean Ruppenthal (Bergische Universität Wuppertal)
Canonical sheaves at isolated canonical singularities
The canonical line bundle and the corresponding canonical sheaf belong to the most important geometric/analytic objects associated to a complex manifold. They play a crucial role e.g. in classification theory, Serre duality or vanishing theorems. If we consider singular varieties instead of smooth manifolds, then there exist various possibilities to generalize the canonical sheaf to that setting. One can consider for example the Grothendieck(-Barlet-Henkin-Passare) dualizing sheaf or the Grauert-Riemenschneider L2-sheaf. In this talk, we will discuss another possible generalization, i.e., the sheaf of L2 holomorphic n-forms with a certain boundary condition at the singular set. This sheaf is essential for L2-dbar-theory on singular spaces, but difficult to understand. We will describe it explicitly for isolated canonical Gorenstein singularities.
Per informazioni, rivolgersi a: pezzini@mat.uniroma1.it
Mercoledì 09 giugno 2021
Ore 14:30, https://meet.google.com/pip-kvzt-fkz, Dipartimento di Fisica, Sapienza Università di Roma
Seminario delle Meccaniche
Luigi Galgani e Andrea Carati (Università di Milano)
Kirchhoff's thermal radiation law, the Oseen-Wheeler-Feynman cancellation and the Einstein Classical Program
Kirchhoff's thermal radiation law (emission proportional to surface rather than to volume, 1859) is still unexplained in microscopic terms. Here it is shown how it can be explained as corresponding to the Oseen-Wheeler-Feynman cancellation property of classical electrodynamics of particles, which was conjectured by those authors, and in the meantime was proven. Then we address the Einstein Classical Program: to "explain" quantum mechanics in "realistic" terms. We point out how the O-W-F cancellation removes the main objection against implementing the Einstein Program in terms of particle trajectories (fall of electrons to nuclei due to radiation emission). Two examples are illustrated: infrared spectra of ionic crystals, and chemical bond in the ion of the Hydrogen molecule. Furthermore, an explanation is given of the existence of polaritons, a phenomenon concerning ionic crystals, still unexplained in a quantum frame.
Mercoledì 09 giugno 2021
Ore 16:00, Online seminar, Dipartimento di Matematica, Università di Roma "Tor Vergata"
Seminario Algebre di Operatori
Laszlo Zsido (Università di Roma Tor Vergata)
On the equality and inequality of weights and operator valued weights
Abstract: https://drive.google.com/file/d/1yiNWmwSC334XRmH9FByqrLv_Fa1ileUL/view?usp=sharing. This talk is part of the activity of the MIUR Excellence Department Project MATH@TOV CUP E83C18000100006. Link
Per informazioni, rivolgersi a: v.morinelli@gmail.com
Giovedì 10 giugno 2021
Ore 14:00, Seminario online su questo link, Dipartimento di Matematica, Università di Roma "Tor Vergata"
Seminario di Analisi Matematica
Francesco Palmurella (ETH Zürich)
The parametric approach to the Willmore flow
We introduce a parametric framework for the study of Willmore gradient flows which enables to consider a general class of weak, energy-level solutions and opens the possibility to study energy quantization and finite-time singularities. In this first work we restrict to a small-energy regime and prove that, for small-energy weak immersions, the Cauchy problem in this class admits a unique solution. Joint work with T. Rivière.
NB:This talk is part of the activity of the MIUR Excellence Department Project MATH@TOV CUP E83C18000100006
Per informazioni, rivolgersi a: molle@mat.uniroma2.it
Giovedì 10 giugno 2021
Ore 14:30, Canale Youtube Cnr-Iac https://www.youtube.com/watch?v=nYwkplQQbEg, Istituto per le Applicazioni del Calcolo - Consiglio Nazionale delle Ricerche
Seminari Generali IAC 2021
Donatella Granata (Istituto per le Applicazioni del Calcolo - Consiglio Nazionale delle Ricerche)
Interdiction Networks and Critical Disruption Path problem
Many real-life optimization problems can accurately be represented as networks, this talk will be structured in two main parts. In the first one, we will introduce how it is important from interdiction perspectives to predict and evaluate the behavior of the system, via measuring the rules governing individual vertices, edges, or associated substructures, whose malfunctioning prevents the functionality of the network as a whole. In the second part, we will deal with the Critical Disruption Path problem presenting some variants and exact and meta-heuristics procedures to face it.
Per informazioni, rivolgersi a: roberto.natalini@cnr.it
Venerdì 11 giugno 2021
Ore 15:00, Seminario Telematico, Link
Online Representation Theory Seminar
Lucien Hennencart (Université de Paris-Saclay)
Perverse sheaves with nilpotent singular support for curves and quivers
Perverse sheaves on the representation stacks of quivers are fundamental in the categorification of quantum groups. I will explain how to prove that semisimple perverse sheaves with nilpotent singular support on the stack of representations of an affine quiver form Lusztig category and how to extend this question to quivers with loops. The analogous question for curves is to determine perverse sheaves on the stack of coherent sheaves whose singular support is a union of irreducible components of the global nilpotent cone. We solve this problem for elliptic curves, for which we also show that the characteristic cycle map induces a bijection between simple Eisenstein spherical perverse sheaves and irreducible components of the global nilpotent cone. This constitutes a step towards the understanding of the degree zero part of the cohomological Hall algebra of a curve.
Le comunicazioni relative a seminari da includere in questo notiziario devono pervenire esclusivamente
mediante apposita form da compilare online, entro le ore 24 del giovedì precedente la settimana
interessata. Le comunicazioni pervenute in ritardo saranno ignorate.
Per informazioni, rivolgersi all'indirizzo di posta elettronica
seminari@mat.uniroma1.it.
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