- Random - Mailing list — Dipartimento di Matematica, UniPI

Probability Seminar: Alessandra Cipriani (TU Delft) [Padova 31/01, 11.30]
by alessandra bianchi 21 Jan '20

21 Jan '20

Dear Colleagues, we would like to invite you to the following Probability seminar that will take place at the Department of Mathematics of Padova, on January 31. ________________________________________________________ Speaker: Alessandra Cipriani (TU Delft) Title: Dynamical fitness models: evidence of universality classes for preferential attachment 31 JANUARY (Friday), 11:30; ROOM 1BC45, Dipartimento di Matematica “Tullio Levi-Civita”, Via Trieste 63, Padova Abstract: In this talk we study different variations of a particular class of random graphs called preferential attachment models with fitness. These are dynamic graphs in which, at every time step, a new node attaches itself to an older one with probability proportional to the degree and a random factor associated to the node, called the fitness. Motivated by learning mechanisms of real-life networks, we assume the fitness to be a Moving Average process MA(q) with positive increments. We study different properties of such models, for example the degree distribution, the attachment probability and the phenomenon of Bose-Einstein condensation. Finally we provide evidence that, tuning the parameters of the fitness process, we fall into two universality classes represented by the well-known Albert-Barabàsi model and Bianconi-Barabàsi model. This implies the robustness of heavy tails in the degree distribution under random perturbations of the attachment rule. All of you are very welcome. Best regards, Alessandra Bianchi -- Alessandra Bianchi Dip. di Matematica Università di Padova Via Trieste, 63 - 35121 Padova, Italy phone: +39 049 827 14 06 fax: +39 049 827 14 28 e-mail: bianchi(a)math.unipd.it http://www.math.unipd.it/~bianchi/

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BFS World Congress in Hong Kong 2020: Special Issue of Mathematical Finance and Reconfirmation of Lectures (fwd)
by Tiziano Vargiolu 21 Jan '20

21 Jan '20

---------- Forwarded message ---------- Date: Tue, 21 Jan 2020 12:27:19 +0000 From: Office Bachelier Finance Society <office(a)bachelierfinance.org> Subject: BFS World Congress in Hong Kong 2020: Special Issue of Mathematical Finance and Reconfirmation of Lectures 12th World Congress of the Bachelier Finance Society SPECIAL ISSUE OF MATHEMATICAL FINANCE AND RECONFIRMATION OF LECTURES Dear Tiziano Vargiolu We are pleased to announce that a special issue of Mathematical Finance has been arranged for papers presented at the BFS World Congress in Hong Kong. Details will be available through the website soon. We are also delighted to report that Robert Merton has reconfirmed his delivery of the Louis Bachelier Lecture and all the 9 plenary speakers have reconfirmed their participation at the Congress. The deadline, January 31, 2020, for submitting abstracts to the 2020 Bachelier World Congress is approaching fast (http://www1.se.cuhk.edu.hk/~bfs2020/) Finally, the reservation of the Conference Hotel at discounted rates is open (http://www1.se.cuhk.edu.hk/~bfs2020/accommodation/accommodation.html) We are looking forward to seeing you at this unique event in Hong Kong. Nan Chen, Duan Li, Xunyu Zhou Organizers of the 2020 BFS World Congress Hong Kong Copyright ? 2020 Bachelier Finance Society, All rights reserved. You are receiving this email because you opted in via our website. Our mailing address is: Bachelier Finance SocietyRaemistrasse 101 Z?rich 8092 Switzerland Add us to your address book Want to change how you receive these emails? You can update your preferences or unsubscribe from this list.

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Seminario all'IAC
by torrisi＠iac.rm.cnr.it 21 Jan '20

21 Jan '20

Si comunica che il 30 gennaio 2020 alle ore 14.00 presso l'Aula Riunioni dell'Istituto per le Applicazioni del Calcolo (sede di Roma) si terrà il seguente seminario: Relatore: Professor Alberto Lanconelli (Universita' di Bologna) Titolo: Absolute continuity and Fokker-Planck equation for the law of Wong-Zakai approximations of Ito SDEs Abstract: We investigate the regularity of the law of Wong-Zakai-type approximations for Ito stochastic differential equations. These approximations solve random differential equations where the diffusion coefficient is Wick-multiplied by the smoothed white noise. Using a criterion based on the Malliavin calculus we establish absolute continuity and a Fokker-Planck-type equation solved in the distributional sense by the density. The parabolic smoothing effect typical of the solutions of Ito equations is lacking in this approximated framework; therefore, in order to prove absolute continuity, the initial condition of the random differential equation needs to possess a density itself. -- *Giovanni Luca Torrisi Consiglio Nazionale delle Ricerche, Rome, Italy Homepage: http://www.iac.rm.cnr.it/~torrisi/* * *

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Seminario di Francesco Caravenna a Roma 1
by Faggionato, Alessandra 21 Jan '20

21 Jan '20

Buongiorno Lunedì 27.01 alle 16:00 Francesco Caravenna (Università di Milano-Bicocca) terrà il seguente seminario in Sala di Consiglio del Dipartimento di Matematica La Sapienza. Title: On the two-dimensional KPZ and Stochastic Heat Equation Abstract: We consider the Kardar-Parisi-Zhang equation (KPZ) and the multiplicative Stochastic Heat Equation (SHE) in two space dimensions, driven by with space-time white noise. These singular PDEs are "critical" and lack a solution theory, so it is standard to consider regularized versions of these equations - e.g. convolving the noise with a smooth mollifier - and to investigate the behavior of the regularized solutions when the regularization is removed. Based on joint works with Rongfeng Sun and Nikos Zygouras, we show that these regularized solutions undergo a phase transition as the noise strength is varied on a logarithmic scale, with an explicit critical point. In the sub-critical regime, the regularized solutions of both KPZ and SHE exhibit so-called Edwards-Wilkinson fluctuations, i.e. they converge to the solution of the *additive* Stochastic Heat Equation (after centering and rescaling), with a non-trivial constant on the noise. We finally discuss the critical regime, where many questions are open. Grazie Saluti Alessandra -- ************************************************* Prof. Alessandra Faggionato http://www1.mat.uniroma1.it/~faggionato/ Department of Mathematics University "La Sapienza" Piazzale Aldo Moro, 5 00185 - Rome Office 5, Phone (0039) 06 49913252 *************************************************

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Complexity72h Call for Tutors
by Mateusz Wilinski 19 Jan '20

19 Jan '20

Dear colleagues, We are glad to announce the *third edition of the Complexity72h workshop*, which will take place at LUISS, Rome, Italy, on *July 1-4 2020*, as pre-event of the *NetSci 2020* Conference. Complexity72h is an interdisciplinary workshop whose aim is to bring together young researchers from different fields of complex systems and complex networks. Participants form teams and carry out projects in a three days' time, i.e. 72 hours. The goal of each team is to upload on the arXiv a report of their work by the end of the event. The previous two editions have been a success: 11 out of 11 projects have become arXiv preprints and new collaborations have been born. Each team will have a tutor that: 1. designs and proposes the project; 2. supervises its execution; 3. provides the necessary knowledge and data. *Do you want to become a Complexity72h tutor?* We are opening a *call for tutors* targeting researchers in complex systems and networks. We are looking for people who wish to propose a stimulating project to a team of highly motivated students and postdocs, and have the stamina to carry it out in 72 hours. But is it really possible to do it in just 72 hours? To succeed, we need: 1. A motivated and multidisciplinary team of resilient researchers; 2. A comfortable research environment and supportive staff; 3. A solid and feasible research project and a tutor who can make it happen. We provide the first two. It is up to you to provide the last point. *Send your project proposal (title and abstract) and short CV to: complexity72h [at] gmail [dot] com* , or get in touch with us as soon as possible if you have any questions. *The call for tutors deadline is February 7th, 2020.* Looking forward to your ideas. Complexity72h Organizers

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7th Workshop on Stochastic Methods in Game Theory
by Marco Scarsini 17 Jan '20

17 Jan '20

The 7th Workshop on Stochastic Methods in Game Theory will take place in Erice July 1-8, 2020. https://sites.google.com/view/erice-smgt2020/the-workshop The workshop will include some tutorials that could be particularly useful to graduate students and young researchers. Some slots are still available for contributors who want to present a poster. ******************************************************* Marco Scarsini Dipartimento di Economia e Finanza Luiss Viale Romania 32 00197 Roma, ITALY URL: http://docenti.luiss.it/scarsini/

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avviso di due seminari a Napoli
by Enrica Pirozzi 17 Jan '20

17 Jan '20

-- AVVISO DI SEMINARI DI PROBABILITÀ E STATISTICA MATEMATICA Title: The risk model with stochastic premiums and a multi-layer dividend strategy by Olena Ragulina Faculty of Mechanics and Mathematics, Taras Shevchenko National University of Kyiv Abstract: The lecture is devoted to a generalization of the risk model with stochastic premiums where dividends are paid according to a multi-layer dividend strategy. First of all, we derive piecewise integro-differential equations for the Gerber-Shiu function and the expected discounted dividend payments until ruin. Next, we concentrate on the detailed investigation of the model in the case of exponentially distributed claim and premium sizes and find explicit formulas for the ruin probability as well as for the expected discounted dividend payments. Moreover, we obtain an exponential bound for the ruin probability under certain conditions and study these conditions for some special distributions of claim and premium sizes. Lastly, numerical illustrations for some multi-layer dividend strategies are presented. -- Title: The first-passage time properties of the Jacobi process and applications to neuronal modeling by Giuseppe D'Onofrio Dipartimento di Matematica "Giuseppe Peano", Università di Torino Abstract: Nonlinear dynamical systems are often affected by different sources of noise and the usual belief is that the presence of noise can hinder or deteriorate the signal transmission in the system. However it has been observed, both in theoretical models and experiments, that random fluctuations can sometimes improve information processing. Mathematical models in neuroscience are one of the most prominent examples of phenomena for which the noise is of primary importance or even a part of the signal itself rather than a source of inefficiency and unpredictability. Our aim is to contribute to the discussion on the role of noise, studying the effects of a multiplicative noise on the performance of single neuron models using an analytical approach on the related first-passage-time problem. We consider a model where the evolution of the neuronal membrane depolarization between two consecutive spikes is described by a Jacobi process. We analyze the spiking activity of the neuron under study through the firing rate and the variability of the output related to the first two moments of the random variable first-passage time and we describe the occurrence of a phenomenon of coherence resonance. In particular we present counterintuitive effects due to the presence of the multiplicative noise and its dependence on the input parameters. Based on joint work with Petr Lansky (Czech Academy of Sciences) and Massimiliano Tamborrino (University of Warwick). I seminari si terranno il 23 Gennaio 2020 ore 15:00 e ore 15:45, rispettivamente, in Aula G terzo livello del Dipartimento di Matematica e Applicazioni, Università di Napoli FEDERICO II, Complesso di Monte Sant'Angelo, Via Cintia, Napoli. -- Enrica Pirozzi Dipartimento di Matematica e Applicazioni Universita' di Napoli FEDERICO II Via Cintia, Monte S.Angelo, 80126, NAPOLI, ITALY Tel. 081 675634 https://www.docenti.unina.it/ENRICA.PIROZZI

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Seminario at Scuola Normale Superiore, Tiziano De Angelis, School of Mathematics, The University of Leeds (January 22, 2020, 11:30)
by Giulia Livieri 17 Jan '20

17 Jan '20

Dear all, On Wednesday, 22 January 2020 — at 11:30 — at the Scuola Normale Superiore (Room: Aula Fermi) Dr Tiziano De Angelis (University of Leeds) will hold the following Seminar: Title Probabilistic results concerning smoothness of the value function and of the free boundary in optimal stopping Abstract I will present probabilistic proofs of some regularity properties for the value function of general optimal stopping problems and for the associated optimal boundaries. In particular this talk focuses on C^1 regularity of the value function and Lipschitz continuity of the optimal boundary. Most of our arguments rely on fundamental concepts from the theory of Markov processes and bridge the probabilistic and the analytical strands of the literature on free boundary problems. I will also illustrate situations in which our work improves or complements known facts from PDE theory. (based on https://epubs.siam.org/doi/pdf/10.1137/17M1113709 <https://epubs.siam.org/doi/pdf/10.1137/17M1113709> and https://arxiv.org/abs/1812.04564 <https://arxiv.org/abs/1812.04564>) Feel free to forward this announcement to your colleagues. Best Giulia Livieri

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Seminar Cuturi @Bocconi
by Giacomo Zanella 16 Jan '20

16 Jan '20

We kindly invite you to the following BIDSA seminar: “Differentiable Ranking and Sorting using Optimal Transport” Marco Cuturi (Google Brain / ENSAE) Friday, January 17, 2020 | 12:30 | Room 3-e4-sr03 (third floor) Bocconi University, Via Roentgen 1, Milan Abstract: We propose in this paper proxy operators for ranking and sorting that are differentiable. To do so, we leverage the fact that sorting can be seen as a particular instance of the optimal transport (OT) problem between two univariate uniform probability measures, the first measure being supported on the family of input values of interest, the second supported on a family of increasing target values (e.g. 1,2,...,n if the input array has n elements). Building upon this link, we propose generalized rank and sort operators by considering arbitrary target measures supported on m values, where m can be smaller than n. We recover differentiable algorithms by adding to this generic OT problem an entropic regularization, and approximate its outputs using Sinkhorn iterations. To illustrate the versatility of these operators, we use the soft-rank operator to propose a new classification training loss that is a differentiable proxy of the 0/1 loss. Using the soft-sort operator, we propose a new differentiable loss for trimmed regression. Speaker: Marco Cuturi joined Google Brain, in Paris, in October 2018. He graduated from ENSAE (2001), ENS Cachan (Master MVA, 2002) and holds a PhD in applied maths obtained in 2005 at Ecole des Mines de Paris. He worked as a post-doctoral researcher at the Institute of Statistical Mathematics, Tokyo, between 11/2005 and 3/2007. He worked in the financial industry between 4/2007 and 9/2008. After working at the ORFE department of Princeton University between 02/2009 and 08/2010 as a lecturer, he was at the Graduate School of Informatics of Kyoto University between 9/2010 and 9/2016 as a tenured associate professor from 10/2013. He then joined ENSAE, the french national school for statistics and economics, in 9/2016, where he still teaches. His recent proposal to solve optimal transport using an entropic regularization has re-ignited interest in optimal transport and Wasserstein distances in the machine learning community. His work has recently focused on applying that loss function to problems involving probability distributions, e.g. topic models / dictionary learning for text and images, parametric inference for generative models, regression with a Wasserstein loss and probabilistic embeddings for words. Best regards, Giacomo Zanella Please note: if you are a guest and you do not have a Bocconi ID Card to access to the Bocconi Buildings, please communicate your participation by sending an email to c.monetti(a)unibocconi.it

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Ernesto De Vito @ Roma Tor Vergata
by Anna Vidotto 16 Jan '20

16 Jan '20

Dear all, I would like to announce the following talk that will be held on Thursday January 23rd 2020, at 4:30 PM, in Aula D’Antoni of the Department of Mathematics, University of Rome Tor Vergata. Speaker: Ernesto De Vito Title: Multi-Scale Vector Quantization with Reconstruction Trees Abstract: The aim of vector quantization is a parsimonious reconstruction of unsupervised data as provided by K-means and geometric multi-resolution analysis, to name a few. In the talk I will present a multi-scale algorithm for vector quantization and study its statistical properties. The proposed approach is inspired by decision trees and is based a family of given partitions, to quickly explore the data in a coarse to fine-multi-scale-fashion. The main technical contribution is an analysis of the expected distortion achieved by the proposed algorithm. Both asymptotic and finite sample results are derived. The presentation is based on a joint work with E. Cecini and L. Rosasco. Kind regards --------- Anna Vidotto PostDoc Researcher Dipartimento di Matematica Università degli Studi di Roma Tor Vergata https://sites.google.com/view/annavidotto

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