Notiziario Scientifico
a cura del Dipartimento di Matematica Guido Castelnuovo, Sapienza Università di Roma
Settimana dal 15-04-2024 al 21-04-2024
Lunedì 15 aprile 2024
Ore 14:00, Aula Dal Passo, Dipartimento di Matematica, Università di Roma Tor Vergata
corso di dottorato
Martina Lanini (Tor Vergata)
Algebre di Hecke
Lunedì 15 aprile 2024
Ore 14:30, Sala di Consiglio, Dipartimento di Matematica, Sapienza Università di Roma
seminario di Analisi Matematica
Roberto Monti (Università di Padova)
Il problema della regolarità delle geodetiche sub-Riemanniane // The regularity problem of sub-Riemannian geodesics.
IT: Presenteremo lo stato dell'arte sul problema della regolarità delle curve minime della lunghezza in varietà sub-Riemanniane, un problema aperto da almeno 40 anni. Il seminario avrà un carattere analitico, informale e introduttivo ma arriveremo a parlare di risultati molto recenti ottenuti con vari collaboratori. // EN: We shall discuss the open problem about the regularity of sub-Riemannian length minimizing curves. The seminar will be analytically oriented, informal and accessible but we shall also present some recent results obtained with various co-authors. This seminar is part of the activities of the Dipartimento di Eccellenza CUP B83C23001390001 and it is funded by the European Union – Next Generation EU.
Per informazioni, rivolgersi a: azahara.delatorrepedraza@uniroma1.it
Martedì 16 aprile 2024
Ore 11:00, Aula Dal Passo, Dipartimento di Matematica, Università di Roma Tor Vergata
corso di dottorato
Martina Lanini (Tor Vergata)
Algebre di Hecke
Martedì 16 aprile 2024
Ore 14:30, Aula Dal Passo, Dipartimento di Matematica, Università degli studi di Roma "Tor Vergata"
Seminario di Analisi Numerica
Michael Barton (Basque Center for Applied Mathematics)
Gaussian quadrature rules for univariate splines and their applications to tensor-product isogeometric analysis
Univariate Gaussian quadrature rules for spline spaces that are frequently used in Galerkin discretizations to build mass and stiffness matrices will be discussed. Their computation is based on the homotopy continuation concept that transforms Gaussian quadrature rules from the so called source space to the target space. Starting with the classical Gaussian quadrature for polynomials, which is an optimal rule for a discontinuous odd-degree space, and building the source space as a union of such discontinuous elements, we derive rules for target spline spaces with higher continuity across the elements. We demonstrate the concept by computing numerically Gaussian rules for spline spaces of various degrees, particularly those with non-uniform knot vectors and non-uniform knot multiplicities. We also discuss convergence of the spline rules over finite domains to their asymptotic counterparts, that is, the analogues of the half-point rule of Hughes et al., that are exact and Gaussian over the infinite domain. Finally, the application of spline Gaussian rules in the context of isogeometric analysis on subdivision surfaces will be discussed, showing the advantages and limitations of the tensor product Gaussian rules. This talk is part of the activity of the MUR Excellence Department Project MatMod@TOV (CUP E83C23000330006).
Per informazioni, rivolgersi a: speleers@mat.uniroma2.it
Martedì 16 aprile 2024
Ore 14:30, aula D'Antoni, Dipartimento di Matematica, Università di Roma Tor Vergata
seminario di Geometria
Elisabetta Colombo (Università degli studi di Milano)
On the local geometry of the moduli spaces of cubic threefolds in A_5 and of (2,2) threefolds in A_9
We will report on joint works with Paola Frediani, Juan Carlos Naranjo and Gian Pietro Pirola. We study the second fundamental form of the Siegel metric in A_5 restricted to the moduli space of the intermediate jacobians cubic threefolds and the second fundamental form in A_9 restricted to the moduli of the the intermediate jacobians of (2,2) threefolds in P^2xP^2 . In both case there is a natural composition with a multiplication map. For cubic threefold this composition results to be zero, while for (2,2) threefolds it gives a not zero holomorphic section of a bundle.
Per informazioni, rivolgersi a: guidomaria.lido@gmail.com
Martedì 16 aprile 2024
Ore 15:00, Sala di Consiglio, Dipartimento di Matematica, Sapienza Università di Roma
Seminario di Modellistica Differenziale Numerica
Giulia Villani (Sapienza University)
Optimal control for orbital transfer of LEO satellites with Low-Thrust engines
The research project, in collaboration with Thales Alenia Space Italia SpA, aims to study, develop and numerically simulate innovative methods for optimizing the orbital transfer of small satellites in LEO (Low Earth Orbit) using Low-Thrust engines, to be deployed in constellations for Earth observation applications. We developed the controlled dynamics of a single satellite, using the Dynamic Programming approach, based on the characterization of the value function via the Hamilton-Jacobi-Bellman equation. We have built an algorithm that fits a specific physical problem of industrial interest, applying numerical techniques as the Policy Iteration to make the algorithm faster, and using a more suitable grid to save memory. The main challenge is to build a solid control model to satisfy mission objectives and requirements, e.g. the time needed to reach the target orbit, or the use of propellent.
Martedì 16 aprile 2024
Ore 16:00, Aula "Dal Passo", Dipartimento di Matematica, Università di Roma "Tor Vergata"
Seminario di Analisi Matematica
Pietro Majer (Università di Pisa)
On the CW-structure induced by a Morse-Smale gradient flow
A classic yet delicate fact of Morse theory states that the unstable manifolds of a Morse-Smale gradient-flow on a closed manifold M are the open cells of a CW-decomposition of M. I will describe a self-contained proof by Abbondandolo and myself. The key tool is a "system of invariant stable foliations", which is analogous to the object introduced by Palis and Smale in their proof of structural stability of Morse Smale diffeomorphisms and flows, but with finer regularity and geometric properties.
[Stable foliations and CW structure induced by a Morse-Smale gradient flow, A.Abbondandolo,P.Majer] https://www.worldscientific.com/doi/10.1142/S1793525321500527
NB:This talk is part of the activity of the MIUR Excellence Department Project MATH@TOV CUP E83C23000330006
Per informazioni, rivolgersi a: molle@mat.uniroma2.it
Mercoledì 17 aprile 2024
Ore 11:00, Aula Dal Passo, Dipartimento di Matematica, Università di Roma Tor Vergata
corso di dottorato
Martina Lanini (Tor Vergata)
Algebre di Hecke
Mercoledì 17 aprile 2024
Ore 14:00, Sala di Consiglio, Dipartimento di Matematica, Sapienza Università di Roma
Seminario di Algebra e Geometria
Alessio Cela (ETH Zürich)
Fixed-curve counts in algebraic varieties
The counts of algebraic curves in an algebraic variety satisfying specific geometric conditions are referred to as Gromov-Witten invariants of the variety. In my talk, I will focus on these invariants when, in addition, the complex structure of the curve is fixed, explaining the advantages that such a choice affords.
Mercoledì 17 aprile 2024
Ore 16:00, Aula Dal Passo, Dipartimento di Matematica, Università di Roma Tor Vergata
Seminario di Algebre di Operatori
Valeriano Aiello (Sapienza Università di Roma)
Colorazioni, sottogruppi del gruppo di Thompson e rappresentazioni
Circa dieci anni fa, V. Jones introduceva diverse rappresentazioni unitarie dei gruppi di Thompson e vari sottogruppi interessanti sono emersi come stabilizzatori di vettori in queste rappresentazioni. In questo seminario presenterò il lavoro svolto su questo argomento. The Operator Algebra Seminar schedule is here: https://sites.google.com/view/oastorvergata/home-page?authuser=0
Mercoledì 17 aprile 2024
Ore 16:00, Aula primo piano, Istituto per le Applicazioni del Calcolo IAC-CNR Roma
Seminario Volterra
Emanuela Radici (Università degli Studi dell'Aquila)
Deterministic particle approximations for nonlocal transport equations and degenerate second order traffic models
In this talk we discuss a deterministic particle approach for a wide class of scalar nonlinear models, including first and second oder ones describing crowd dynamics. The congestion term appears in the equation in the form of a compactly supported nonlinear mobility function, thus making standard weak-type compactness arguments and uniqueness of weak solutions fail. We consider several generalizations of the deterministic Follow-theleader scheme, which can be interpreted as Lagrangian discretisations of the target pdes, and investigate the compactness properties of suitable approximations of the relevant macroscopic quantities. For first order nonlocal transport models we show that such schemes provide in the many particle limit, and under mild assumptions on the potentials, the unique entropy solution in the sense of Kruˇzkov. We then consider second order traffic models in which the drivers’ reaction time depends on both the inertia and a congestion term. In this case, we obtain in the many particle limit suitable weak-type solutions of a degenerate pressurless Euler-type system and we recover the first order model with nonlinear mobility in the joint many-particle/ vanishing-inertia regime.
Mercoledì 17 aprile 2024
Ore 16:30, Aula M2, Dipartimento di Matematica e Fisica, Università degli Studi Roma Tre
Seminario di Analisi Matematica
Francisco Javier Reyes Sanchez (Universidad de Granada)
Prescribing curvatures in the disk via conformal change of the metric
In this talk, we present a general existence result to the problem of prescribing curvatures on a disk under conformal changes of the metric. We treat the case of negative Gaussian curvature, as a first step in this direction we restrict ourselves to a symmetric setting. We also give a non-existence result which shows that the assumptions required for existence are necessary.
Per informazioni, rivolgersi a: luca.battaglia@uniroma3.it
Giovedì 18 aprile 2024
Ore 14:15, Dipartimento di Matematica e Fisica, Università Roma Tre
Seminario Di Geometria
Marco Pacini (Fluminense)
Moduli of roots in algebraic and tropical geometry
In this talk we will consider the moduli space parametrizing roots of line bundles on algebraic curves. Our goal will be the construction of a tropical moduli space of roots of divisors on stable tropical curves. We will discuss the relation between the two moduli spaces, and we will give some applications.
Per informazioni, rivolgersi a: amos.turchet@uniroma3.it
Giovedì 18 aprile 2024
Ore 14:30, Sala di Consiglio, Dipartimento di Matematica, Sapienza Università di Roma
P(n)/N(p) : Problemi differenziali nonlineari/Nonlinear differential problems
Marco Pozza (Università di Roma Tor Vergata)
Homogenization of Hamilton-Jacobi Equations posed on Networks
We extend the celebrated result by Lions, Papanicolaou and Varadhan (1987) on the homogenization of Hamilton-Jacobi equation to the network setting. Roughly speaking, we aim at describing the macroscopic behavior of solutions to time dependent Hamilton-Jacobi equations posed on periodic networks by averaging over their microscopic oscillations and neglecting their local features. This is done using a variational approach which relies on the Aubry-Mather theory, namely the study of curves or probability measures that minimize the Lagrangian action. This is a joint work with Antonio Siconolfi and Alfonso Sorrentino.
Per informazioni, rivolgersi a: galise@mat.uniroma1.it
Venerdì 19 aprile 2024
Ore 14:30, Aula Dal Passo, Dipartimento di Matematica, U Roma Tor Vergata
Algebra and Representation Theory Seminar
Martina Costa Cesari (U Bologna)
Jordan classes and Lusztig strata in non-connected algebraic groups
Reductive non-connected groups appear frequently in the study of algebraic groups, for example, as centralizers of semisimple elements in non-simply connected semisimple groups. Let G be a non-connected reductive algebraic group over an algebraically closed field of arbitrary characteristic and let D be a connected component of G. We consider the strata in D defined by Lusztig as fibers of a map E given in terms of truncated induction of Springer representations. By the definition of the map E, one can see that elements with the same unipotent part and the same centralizer of the semisimple part are in the same stratum. The connected component of the set collecting the elements with these properties are called Jordan classes. In his work, Lusztig suggests that the strata are locally closed, and in my work I show this assertion. To prove it, I show that a stratum is a union of the regular part of the closure of Jordan classes. From this result, one can also describe the irreducible components of a stratum in terms of regular closures of Jordan classes.
Venerdì 19 aprile 2024
Ore 16:00, Aula Dal Passo, Dipartimento di Matematica, U Roma Tor Vergata
Algebra and Representation Theory Seminar
Elisabetta Masut (U Padova)
Non-existence of integral Hopf orders for certain Hopf algebras
The study of the (non)-existence of integral Hopf orders was originally motivated by Kaplansky's sixth conjecture, which is a generalization of a Frobenius theorem in the Hopf algebra setting. In fact, Larson proved that a Hopf algebra which admits an integral Hopf order satisfies the conjecture. The aim of this talk is to give a partial answer to the following question: Does a semisimple complex Hopf algebra admit an integral Hopf order? In particular, we will present several families of semisimple Hopf algebras which do not admit an integral Hopf order. These Hopf algebras will be constructed as Drinfeld twists of group algebras. This talk is based on a joint work with Giovanna Carnovale and Juan Cuadra, and on my Ph.D. thesis.
Venerdì 19 aprile 2024
Ore 16:00, Aula Picone, Dipartimento di Matematica, Sapienza Università di Roma
Seminari per i docenti A. A. 2023-2024
Annalisa Cusi, Agnese Telloni & al.
Racconti matematici: un'occasione per stimolare riflessioni sui contenuti e sull'atteggiamento verso la matematica
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.
Coloro che desiderano ricevere questo notiziario via e-mail sono pregati
di comunicare il proprio indirizzo di posta elettronica a
seminari@mat.uniroma1.it.