NumPI January 2025

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Online seminar at University of Rome "Tor Vergata": Stefano Pozza: 6 febbraio alle 12:30
by Fabio Durastante 29 Jan '25

29 Jan '25

Dear everybody, Forwarding of a NA seminar announcement that can also be followed online at the University of Rome "Tor Vergata". Best, Fabio ________________________________ Da: Mariarosa Mazza <mariarosa.mazza(a)uniroma2.it> Inviato: mercoledì 29 gennaio 2025 18:49 A: mariarosa.mazza(a)uniroma2.it Oggetto: seminario Pozza: 6 febbraio alle 12:30 Car* tutt*, giovedi 6 febbraio alle 12.30 in aula Dal Passo, Dipartimento di Matematica, Roma Tor Vergata, il Dott. Stefano Pozza (Charles University) terrà un seminario dal titolo (abstract in calce): "How to express the solution of an ODE as a linear system (in a suitable algebra) and exploit it for fast computation and network analysis". Il seminario può essere seguito online usando il link: https://teams.microsoft.com/l/meetup-join/19%3ad48916dee7364e0bbb08216ea621… Vi prego di diffondere l'annuncio fra i possibili interessati. Un caro saluto e grazie, Mariarosa --------------------------------------- Abstract: The solution of systems of non-autonomous linear ordinary differential equations is crucial in various applications, such as nuclear magnetic resonance spectroscopy. We introduced a new solution expression in terms of a generalization of the Volterra composition. Such an expression is linear in a particular algebraic structure of distributions, which can be mapped onto a subalgebra of infinite matrices. It is possible to exploit the new expression to devise fast numerical methods for linear non-autonomous ODEs. As a first example, we present a new method for the operator solution of the generalized Rosen-Zener model, a system of linear non-autonomous ODEs from quantum mechanics. The new method’s computing time scales linearly with the model’s size in the numerical experiments. A second example is the analysis of temporal network, where the new expression might lead to novel extension of subgraph centrality indexes. -- ------------------------------------- Dr. Mariarosa Mazza University of Rome Tor Vergata Via della Ricerca Scientifica, 1 00133, Rome, Italy Email: mariarosa.mazza(a)uniroma2.it<mailto:mariarosa.mazza@uniroma2.it> Tel: 0039 06-7259-4636 Url: https://sites.google.com/site/mariarosamazza1/ ---------------------------------

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Online Seminar: Peter Taylor, "The Role of Physical Understanding in Matrix-Analytic Methods"
by Federico Poloni 14 Jan '25

14 Jan '25

In case someone is interested, let me share this online event. A flyer is attached. Speaker: Professor Peter Taylor, The University of Melbourne Date: Thursday, February 6 2025 Time: 22:00 Italian time (!!) Title: The Role of Physical Understanding in Matrix-Analytic Methods Abstract: Since Marcel Neuts first showed that Markov chains of GI/M/1 type have a matrix-geometric stationary distribution in the 1970s and 1980s, the interplay between analytic properties and physical interpretation has played a major part in the development of matrix-analytic methods for stochastic models. Most performance measures of interest in such models can be expressed in terms of the solutions of equations involving matrix power series, which have to be solved numerically. Over the years, various iterative algorithms have been proposed for doing this. In order to establish convergence, and gain information about the speed of convergence, it is often helpful to think about the physical interpretation of the iterates. I shall discuss the physical interpretation of matrix-analytic algorithms that have been proposed for analysing block-structured Markov additive models. -- --Federico Poloni Dipartimento di Informatica, Università di Pisa https://www.di.unipi.it/~fpoloni/ tel:+39-050-2213143

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NumPI January 2025