October 2018 - Random - Mailing list — Dipartimento di Matematica, UniPI

Concorso da RTDb di MAT/06 a Padova - scadenza 25/8/2016
by Marco Ferrante 25 Jun '24

25 Jun '24

Cari colleghi, vi segnalo che il Dipartimento di Matematica dell'Università di Padova ha bandito un posto di ricercatore di tipo B nel settore MAT/06. Il bando è disponibile alla pagina http://www.math.unipd.it/it/news/?id=1898 La scadenza per la presentazione delle domande è il 25 agosto 2016. Marco Ferrante

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Seminario KOLOKOLTSOV @ UniTo
by Cristina Zucca 14 Oct '19

14 Oct '19

********************************************************************* SEMINARI DI PROBABILITA' E STATISTICA MATEMATICA DIPARTIMENTO DI MATEMATICA "G. PEANO" UNIVERSITA' DEGLI STUDI DI TORINO ********************************************************************* Martedì 17 Aprile 2018 alle ore 15:00 in Aula Marro presso il Dipartimento di Matematica "G. Peano" dell'Università degli Studi di Torino, Via Carlo Alberto 10, Il Prof. *VASSILI KOLOKOLTSOV* terrà un seminario dal titolo *Recent developments in probabilistic and analytic methods for fractional differential equations * Abstract: We shall discuss recent achievements in solving fractional differential equations and their extensions arising from generalized fractional calculus. Probabilistic techniques will be derived from the notion of Markov processes interrupted on the attempt to cross the boundary. Analytic techniques will cover generalized operator-valued Mittag-Leffler functions and chronological Feynman-Kac formulas. Tutti gli interessati sono invitati a partecipare. -- Dr. Cristina Zucca Department of Mathematics University of Torino Via Carlo Alberto 10 10123 Torino, Italy tel: +39-011-6702850 fax: +39-011-6702878

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Postdoc position in Geometric Methods for Machine Learning and Deep Learning at RIST
by Luigi Malagò 14 Dec '18

14 Dec '18

=========================================================== *Subject*: Postdoc position in Machine Learning (1 year, renewable up to 2 years) *Institution*: RIST - Romanian Institute of Science and Technology, Cluj-Napoca *Keywords*: Geometry of Latent Spaces, Optimization over Manifolds, Information Geometry, Natural Gradient, Riemannian Geometry *Application deadline*: 10 October 2018 (applicants are encouraged to apply earlier) *Salary*: around 2200 euro net *Official announcement*: http://rist.ro/en/details/news/postdoc-positions-in-deep-learning-and-machi… =========================================================== Dear colleagues, the Romanian Institute of Science and Technology (RIST) has an opening for a postdoc position, in the context of the DeepRiemann project “Riemannian Optimization Methods for Deep Learning”, funded by European structural funds through the Competitiveness Operational Program (POC 2014-2020). The appointments will be for 1 year, with possible extensions up to 2 years. The DeepRiemann project aims at the design and analysis of novel training algorithms for Neural Networks in Deep Learning, by applying notions of Riemannian optimization and differential geometry. The task of the training a Neural Network is studied by employing tools from Optimization over Manifolds and Information Geometry, by casting the learning process to an optimization problem defined over a statistical manifold, i.e., a set of probability distributions. The project is highly interdisciplinary, with competences spanning from Machine Learning to Optimization, Deep Learning, Statistics, and Differential Geometry. The objectives of the project are multiple and include both theoretical and applied research, together with industrial activities oriented to transfer knowledge, from the institute to a startup or spin-off of the research group. The positions will be part of the new Machine Learning and Optimization group https://rist.ro/en/teams.html, which performs research at the intersection of Machine Learning, Stochastic Optimization, Deep Learning, and Optimization over Manifolds, using geometric methods based on Information Geometry. The group is one of two newly-formed groups in Machine Learning at RIST. The official job announcement can be seen here: http://rist.ro/en/details/news/postdoc-positions-in-deep-learning-and-machi… Informal inquiries can be sent to Dr. Luigi Malagò <malago(a)rist.ro>, principal investigator of the DeepRiemann project. Application deadline: 10 October 2018 (applicants are encouraged to apply earlier) best regards, Luigi Malagò

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A Summer Day in Probability and Statistical Physics
by Francesca Romana Nardi 16 Nov '18

16 Nov '18

Carissimi, la prossima giornata di seminari sara` il 14 Settembre 2018. Ricordo che ciascuno oratore fara` una lezione introduttiva e divulgativa di 45 minuti pensata proprio per i non esperti, seguita da altri 45 minuti di tipo seminario (vedi programma). Maggiori informazioni e aggiornamenti sulle giornate passate e future sono reperibili alla pagina web che vi invitiamo a visitare periodicamente. http://web.math.unifi.it/users/fnardi/seminari/ A SUMMER DAY IN PROBABILITY AND STATISTICAL PHYSICS University of Florence Friday 14 September 2018 Lecturers: Stefano Olla (Paris) and Raúl Rechtman (Mexico) Location: Aula Magna di Via S. Gallo 10, Firenze Prof. Stefano Olla (Universite` Paris Dauphine) Title: Hyperbolic Hydrodynamic Limits Abstract: I will present a review of old and new results (and open problems) concerning scaling limits for conservation laws in the hyperbolic space-time scale, for a system of anharmonic oscillators with external boundary tension. The macroscopic equation is given by the compressible Euler system, with corresponding boundary conditions. The problem is particularly challenging when shockwaves are present. Some results exists when the microscopic dynamics is perturbed by a conservative stochastic viscosity. Works in Collaboration with Stefano Marchesani (GSSI) and Lu Xu (CEREMADE). Prof. Raúl Rechtman, (Universidad Nacional Autónoma de México) Title: Chaos and damage spreading in a probabilistic cellular automaton Abstract: Deterministic Boolean cellular automata (CA) are discrete maps F:BN → BN, B={0,1}, x(t+1)=F(x(t)) with x ϵ BN, N large and t=0,1,… . The vector x is the state of the cellular automaton with components xi,, i=0,…,N-1 the state of cell I. Each cell is connected to others, generally in a uniform and local way, and one can define an adjacency matrix aij=1 is cell j is connected to cell i and zero otherwise. The global map F is determined by the parallel application of a local function f, such that xi(t+1) = f(vi(t)), where vi denotes the state of cells connected to cell i. Deterministic CA are thus the discrete equivalent of dynamical systems, and many concepts like trajectory (the sequence of configurations x(t)), fixed points and limit cycles can be used. There are cellular automata for which a small modification in an initial configuration propagates to the whole system, a situation similar to chaos in continuous systems, and indeed one can extend the concept of the largest Lyapunov exponent to deterministic CA using Boolean derivatives. One of the main inconvenient is that these systems do not have continuous parameters to be tuned, in order to study bifurcations. In probabilistic cellular automata, the function f (and thus F) is defined in terms of transition probabilities so that deterministic CA can be seen as the extreme cases of probabilistic ones, when the transition probabilities are either zero or one. Probabilistic CA can be seen also as Markov chains, and one can observe interesting phase transitions after changing the transition probabilities that are therefore continuous control parameters. A realization of a specific trajectory is determined by the extraction of one or more of random numbers for each cell. By extracting these numbers at the beginning of the simulation, for all cells and all times, one converts a probabilistic CA into a deterministic one, running over a quenched random field. One can therefore use the concepts of deterministic CA, like damage spreading and maximum Lyapunov exponent also for probabilistic CA, with the advantage of having the possibility of fine-tuning the control parameters. In particular, we investigate a probabilistic cellular automaton which can be considered an extension of a model in the universality class of directed percolation models, but with two absorbing states. In the first part of the talk all the concepts mentioned above are defined and in the second part, the probabilistic cellular automaton is studied numerically. We show that the phase transitions when the order parameter is the average damage do not coincide with those found for the Lyapunov exponent and the reason of this is the presence of absorbing states. Program: 11.00-11.45 Introductory lecture: Olla 11.45-12.00 Break 12.00-13.00 Seminar: Olla 13.00-14.30 Lunch 14.30-15.15 Introductory lecture: Rechtman 15.15-15.30 Break 15.30-16.30 Seminar: Rechtman Organizers: F. Caravenna, N. Cancrini, E.N.M. Cirillo, P. Dai Pra, A. De Masi, D. Fanelli, F. Flandoli C. Giardina`, R. Livi, F. Martinelli, I.G. Minelli, F.R. Nardi, E. Presutti, B. Scoppola, E. Scoppola Note pratiche: 1) E` importante prenotare il biglietto del treno il piu` presto possibile per poter usufruire di sconti!!!! 2) Stiamo prenotando un ristorante (diverso dal precedente) con un paio di menu fissi (di cui uno vegerariano) che possa ospitarci, ma ho bisogno del numero di persone che vogliono mangiare insieme. A coloro che fossero interessati chiedo di mandare un email a francescaromana.nardi(a)unifi.it Resta fermo il fatto che saremo in pieno centro di Firenze, quindi ci sono moltissime altre possibilita` per mangiare se preferite regolarvi indipendentemente. Vi aspettiamo numerosi Francesca R. Nardi Dipartimento di Matematica e Informatica Università degli Studi di Firenze Viale Morgagni 67, Firenze, Italy

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Kolmogorov meets Turing
by Marco Scarsini 16 Nov '18

16 Nov '18

The 5th *Kolmogorov meets Turing (KmT)* Workshop on Stochastics, Optimization, Algorithms, and Games will take place on November 23, 2018 at LUISS Business School, Villa Blanc, Via Nomentana, 216, 00162 Roma. https://sites.google.com/view/kmt2018/home The purpose of KmT is to bring together researchers from Computer Science, Economics, Mathematics and various other fields to present and discuss research on probabilistic methods for the analysis of games, stochastic processes, and randomized algorithms. *The workshop is free but we kindly ask you to register, for logistic purposes.* https://sites.google.com/view/kmt2018/registration ********************************************************Marco ScarsiniDipartimento di Economia e FinanzaLUISSViale Romania 3200197 Roma, ITALYURL: http://docenti.luiss.it/scarsini/ <http://docenti.luiss.it/scarsini/>*

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Torino - Lezione Lagrangiana M. Hairer - 13 Novembre
by Enrico Priola 31 Oct '18

31 Oct '18

Annuncio Lezione Lagrangiana al Dipartimento di Matematica "G. Peano", Universita` di Torino Martedì 13 novembre alle ore 16.30 in Aula A Martin Hairer (Imperial College, London) "Taming Infinities" Abstract: Some physical and mathematical theories have the unfortunate feature that if one takes them at face value, many quantities of interest appear to be infinite! What's worse, this doesn't just happen for some exotic theories, but in the standard theories describing some of the most fundamental aspects of nature. Various techniques, usually going under the common name of “renormalisation” have been developed over the years to address this, allowing mathematicians and physicists to tame these infinities. We will tip our toes into some of the conceptual and mathematical aspects of these techniques and we will see how they have recently been used to study equations whose meaning was not even clear until now. Tutti gli interessati sono invitati a partecipare. Enrico Priola Dipartimento di Matematica Universita' di Torino via Carlo Alberto 10, 10123 TORINO, Italy tel +39 011 6702883 fax +39 011 6702878

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The Aldous spectral gap phenomenon: seminario di Filippo Cesi il 14-11-2018 a Roma Tre
by Pietro Caputo 31 Oct '18

31 Oct '18

Prof. Filippo Cesi Universita' La Sapienza Roma Titolo: THE ALDOUS' SPECTRAL GAP PHENOMENON Mercoledi' 14 Novembre 2018 ORE 16:00 Dipartimento di Matematica e Fisica Universita' degli Studi Roma Tre Largo San Leonardo Murialdo, 1 - Pal.C - Aula 211 Abstract: Some families of Markov chains have a spectral gap which coincides with the spectral gap of an extremely simplified version of the chain. Another way of restating the same concept is: some families of Cayley graphs have a spectral gap which can be found in a very low dimensional representation of the underlying group. We will present a general approach which could be useful when going fishing for this phenomenon in an arbitrary finite group. Two specific examples will be discussed: the case of the symmetric group which corresponds to the "original" Aldous' spectral gap conjecture, proven in 2010 by Caputo, Liggett and Richthammer, and case of the Weyl group W(B_n) we studied in a recent paper.

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Postdoc - Hokkaido University
by Paolo Dai Pra 30 Oct '18

30 Oct '18

Vi inoltro l'annuncio di una borsa postdoc alla Hokkaido University. Paolo Dai Pra %%%%%%%%%%%%%%%%%%%%%%% I announce a Postdoc position in my group project under the CREST project ``Technology for Computing Revolution for Society 5.0": http://www.jst.go.jp/kisoken/crest/en/research_area/ongoing/areah30-4.html Team Hokkaido is trying to build a new computing system based on the Ising model. The team consists of four groups, one of which is my Mathematical Science Group. There are 11 other members, 4 of which are faculty members, 7 others are graduate students. We are investigating the following problems rigorously: 1. Find a best possible embedding of an Ising model on a irregular graph to an Ising model on a given regular graph. 2. Find the ground state of the above Ising model on the regular graph by a sampler faster than, say, Glauber dynamics. 3. Find how stable the ground state is against noise in coupling coefficients and/or external magnetic fields. 4. Find killer applications of the Ising computer. The posdoc position is a 2-year position, starting from April 2019 the earliest, with possible 2-year extension (depending on performance). The net salary will be ranging from 3,769,524 JPY to 5,689,524 JPY (depending on previous experiences). The deadline of application (send via email a CV and a list of publications to: sakai(a)math.sci.hokudai.ac.jp) is set on December 15, 2018. Best regards, Akira Sakai Department of Mathematics Hokkaido University Nishi 8-chome, Kita 10-jo, Kita-ku Sapporo, Hokkaido 060-0810 JAPAN http://www.math.sci.hokudai.ac.jp/~sakai sakai(a)math.sci.hokudai.ac.jp

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Seminario a Bologna del prof. Macci
by Massimo Campanino 29 Oct '18

29 Oct '18

Il giorno mercoledì 7 novembre alle ore 17 nell'aula al VII piano del Dipartimento di Matematica dell'Università di Bologna in piazza Porta S. Donato 5 il prof. Claudio Macci del Dipartimento di Matematica dell'Università di Roma Tor Vergata terrà un seminario dal titolo Asymptotic behavior of some hitting probabilities for sums of IID Gaussian random sets Abstract: We consider sequences of partial sums of iid Gaussian random sets (with respect to the Minkowski sum) and we study t he asymptotic behavior of some hitting probabilities (of suitable sets of $R^d$) for these partial sums. We also illustrate the use of the importance sampling for the estimation of these hitting probabilities by Monte Carlo simulations. We obtain the analog of well-known results for level crossing probabilities of random walks, and we refer to a version of the classical Cramér's Theorem in large deviations for random compact sets existing in the literature. Joint work with Barbara Pacchiarotti

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Seminario di Probabilita`, Universita` La Sapienza
by Faggionato, Alessandra 26 Oct '18

26 Oct '18

Martedi` 30 Ottobre alle ore 14 in Aula di Consiglio, Dipartimento di Matematica, Universita` La Sapienza, ci sara' il seguente seminario: Speaker: Giacomo di Gesu' (Universita' di Vienna) Title: Small noise asymptotics for stochastic Allen-Cahn equations in finite volume Abstract: We consider lattice approximations of the Allen-Cahn equation on the torus perturbed by small space-time white noise and discuss metastable transition times between the two stable phases. Grazie per l'attenzione ************************************************* 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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Assegno di Ricerca - UNIMI
by Giacomo Aletti 25 Oct '18

25 Oct '18

Gentili Colleghi, vi segnalo che, presso il Dipartimento di Scienze e Politiche Ambientali, Università degli Studi di Milano, è stato bandito un assegno di ricerca di tipo B della durata di 12 mesi nell'ambito del scientifico-disciplinare delle Scienze matematiche e informatiche. BANDO: http://www.unimi.it/ricerca/assegni_ricerca/124378.htm SCADENZA: 16/11/2018. La ricerca si svolge nell'ambito nell’ambito del programma di ricerca dal titolo “Quantitative analysis of agricultural land use changes due to the new greening payment in Lombardy”, e richiede le attività che sono sinteticamente qui riportate: 1) Data cleaning 2) Data integration 3) Model development 4) Code writing 5) Data Analysis 6) Reports/Papers writing Si prega di darne massima diffusione. Cordialmente, Giacomo Aletti -- ------------------------------- Giacomo Aletti, Full Professor (Probability Theory and Mathematical Statistics) Department of Environmental Science and Policy (ESP) ADAMSS Centre (ex MIRIAM) Advanced Applied Mathematical and Statistical Sciences Università degli Studi di Milano Via Saldini, 50 20133 Milano, Italy Tel: +39-02-503.16158 Fax:+39-02-503.16090 Cell: +39-340-9739142

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Seminario tra Geometria e Probabilita' di Daniele Agostini a Roma Tre il 29-10-2018
by Pietro Caputo 23 Oct '18

23 Oct '18

Daniele Agostini (Max-Plank Institute fur Mathematik, Leipzig) Titolo: Discrete Gaussians, theta functions and abelian varieties Lunedi' 29 Ottobre 2018 ORE 14:30 Dipartimento di Matematica e Fisica Universita' degli Studi Roma Tre Largo San Leonardo Murialdo,1 - Pal.C - Aula 009 Abstract The Gaussian distribution is a central object in mathematics and it can be characterised as the unique probability on the real numbers that maximises entropy, for fixed mean and variance. It turns out that the same property can be used to define a discrete Gaussian distribution on the integers. Moreover, the discrete Gaussian is parametrised naturally by the Riemann theta function, and, as such, it has a natural connection to the theory of abelian varieties in algebraic geometry. The aim of the talk is to present this connection and to show how question in probability give rise to natural problems in algebraic geometry and viceversa. This is joint work with Carlos Amendola (TU Munich).

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Workshop in Financial Mathematics in Padova
by Giorgia Callegaro 22 Oct '18

22 Oct '18

Dear colleagues, we are pleased to announce that the (mini) “Workshop in Financial Mathematics” will be held the 12 November 2018 at the Department of Mathematics of the University of Padova. The Workshop will start at 2.30 pm (in “Sala Riunioni” VII floor, stairs B) and it will finish at 6pm. The list of invited speakers is available at the conference website: https://events.math.unipd.it/WFM2018/node/1 There is no registration fee, but all participants are kindly requested to register to the Workshop via the online form available here: https://events.math.unipd.it/WFM2018/node/27 See you in Padova! The organising committee Giorgia Callegaro Martino Grasselli Wolfgang Runggaldier Tiziano Vargiolu -- Giorgia Callegaro Assistant Professor Department of Mathematics - University of Padova Via Trieste 63 , I-35121 Padova - ITALY Tel: +39-0498271481 Fax: +39-0498271499 E-Mail: gcallega(a)math.unipd.it <https://webmail.math.unipd.it/horde3/imp/message.php?mailbox=Sent&index=598#> Personal web-page: https://sites.google.com/site/giogiocallegaro/Home

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(senza oggetto)
by Massimo Campanino 22 Oct '18

22 Oct '18

Il giorno giovedì 15 novembre alle ore 16 nell'aula Seminario 2 del Dipartimento di Matematica dell'Università di Bologna (pazza Porta S. Donato 2) il dott. Gianluca Bosi dell'Università di Bologna terrà un seminario dal titolo Revolving random walks in 2D: analysis of type and winding number. We consider simple random walks on two directed versions of the $\mathbb{Z}^2$ lattice; one characteristic feature of these random walks is that they are bound to revolve, according to the orientation prescribed by the edges. The first model was studied by Campanino and Petritis(‘03) and shown to be transient; the other one appeared recently in a paper by Menshikov et al. (’17), where the authors conjectured its recurrence. We shall indeed confirm this conjecture: our proof is done by considering a continuous analogue of the random walk and then applying the Lyapunov function criteria. On the other hand, we obtain a local limit theorem for the return probabilities of the first random walk, which in particular gives a new proof of transience. Finally, we deduce some results related to the winding number for both random walks. This results are joint work with Y.Peres (Microsoft Research, Redmond) and Y.Hu (University of Washington).

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Fwd: RS&A2019
by Gustavo Posta 22 Oct '18

22 Oct '18

Begin forwarded message: > From: The 19th International Conference on Random Structures and Algorithms <rsa2019(a)amu.edu.pl> > Date: 22 ottobre 2018 13.51.37 GMT+02.00 > To: ukryci-adresaci: ; > Subject: RS&A2019 > > > > The 19th International Conference on > RANDOM STRUCTURES AND ALGORITHMS > Zurich, 15-19 July, 2019 > > > We are pleased to announce that the 19th International Conference on Random Structures and Algorithms "RS&A2019" will be held at the ETH in Zurich, 15-19 July, 2019. > > The list of invited speakers is available at the conference website: https://www.math.ethz.ch/fim/conferences/19th-int-conf-random-structures-al…; > the registration is already open: https://www.math.ethz.ch/fim/conferences/19th-int-conf-random-structures-al…. > > We have some limited funding (in terms of accommodation and a per diem) available for graduate students or postdocs. The application form can be found under the link: https://www.math.ethz.ch/fim/conferences/19th-int-conf-random-structures-al… > > More information will be available soon. > > With best regards, > The organizers > > © 2018 - RSA2019 >

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Assegno di ricerca, Università Milano-Bicocca
by andrea ongaro 22 Oct '18

22 Oct '18

Si informa che presso il Dipartimento di Economia, Metodi Quantitativi e Strategie d’Impresa dell’Università Milano-Bicocca è stato bandito un assegno di ricerca (tipo A1, Junior) della durata di 24 mesi rinnovabili sul tema: “Modelli non standard per dati ad elevata complessità”. SCADENZA: 6 novembre 2018. BANDO: https://www.unimib.it/ateneo/gare-e-concorsi/assegni-ricerca-tipo-a1-a1-typ… Cordialmente Andrea Ongaro

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Seminario BELITSER
by Matteo Ruggiero 22 Oct '18

22 Oct '18

STATISTICS SEMINARS @ COLLEGIO CARLO ALBERTO Venerdì 26 Ottobre 2018, alle ore 12:00, presso il nuovo edificio del Collegio Carlo Alberto, in Piazza Arbarello 8, Torino, si terrà il seguente seminario: ------------------------------------------------ Eduard BELITSER (Vrije Universiteit Amsterdam) ROBUST INFERENCE FOR GENERAL PROJECTION STRUCTURES BY EMPIRICAL BAYES AND PENALIZATION METHODS We develop a general framework of projection structures and study the problem of inference on the unknown parameter within this framework by using empirical Bayes and penalization methods. The main inference problem is the uncertainty quantification, but on the way we solve the estimation and posterior contraction problems as well (also a weak version of structure recovery problem). The approach is local in that the quality of the inference procedures is measured by the local quantity, the oracle rate, which is the best trade-off between the approximation error by a projection structure and the complexity of that approximating projection structure. The approach is also robust in that the stochastic part of the general framework is assumed to satisfy only certain mild condition, the errors may be non-iid with unknown distribution. We introduce the excessive bias restriction (EBR) under which we establish the local (oracle) confidence optimality of the constructed confidence ball. As the proposed general framework unifies a very broad class of high-dimensional models interesting and important on their own right, the obtained general results deliver a whole avenue of results (many new ones and some known in the literature) for particular models and structures as consequences, including white noise model and density estimation with smoothness structure, linear regression and dictionary learning with sparsity structures, biclustering and stochastic block models with clustering structure, covariance matrix estimation with banding and sparsity structures, and many others. Many adaptive minimax results over various scales follow from our local results. (Joint work with N. Nurushev.) ------------------------------------------------ Tutti gli interessati sono invitati a partecipare. Il seminario è organizzato dalla "de Castro" Statistics Initiative (www.carloalberto.org/stats) in collaborazione con il Collegio Carlo Alberto. Cordiali saluti, Matteo Ruggiero --- Matteo Ruggiero University of Torino and Collegio Carlo Alberto www.matteoruggiero.it

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seminar announcement
by Marco Scarsini 19 Oct '18

19 Oct '18

October 25th, 2018 12:00 Room 207 *Department of Economics and Finance* LUISS Viale Romania 32 00196 Roma *Speaker:* Bernhard von Stengel / London School of Economics *Title: * *“Equilibria in the challenge tournament”* *Abstract:* *“Arad and Rubinstein (2013) describe a challenge tournament where n players have a binary choice and play a round-robin tournament where they score against each other randomly for a stake that depends on their choices. The player with the highest total score wins, with ties resolved randomly. They conjecture that for n > 3 the only equilibrium is that all players take the riskier choice. We present work in progress on an elementary proof of this conjecture which is based on a simple dominance argument.”* The calendar of the future seminars can be found at http://economiaefinanza.luiss.it/en/seminari/prossimi-seminari ******************************************************* Marco Scarsini Dipartimento di Economia e Finanza LUISS Viale Romania 32 00197 Roma, ITALY URL: http://docenti.luiss.it/scarsini/

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Winter Workshop on Complex Systems 2019 in Zakopane
by Mateusz Wilinski 18 Oct '18

18 Oct '18

Dear All, next year the Winter Workshop on Complex Systems will be held in Zakopane (Poland) from 4th to 8th February 2019. The event is tailored for PhD students and young scientists working in the broad area of Complex Systems (including problems from Biology, Physics, Finance and Economy, Machine Learning and many more). The call for participation in the 2019 edition is now open and the application deadline is 31st of October. All the details are available at: http://wwcs2019.org The cost of the workshop is just 100 euros, which includes accommodation, food, transport from Cracow, social events and more. Participants will also have the chance to interact and hear lectures from exciting scientist, namely: Fabrizio Lillo, Chiara Poletto, Pere Colet and Piotr Fronczak. I hope to see applications from many of you. :) We would also be really happy, if you could help to spread the information and encourage others to apply. Best wishes, on behalf of the organizing committee Mateusz Wilinski

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Bootstrap percolation: subcritical universality class and oriented percolation - Seminario di Ivailo Hartarsky il 24/10/18 a Roma Tre
by Pietro Caputo 16 Oct '18

16 Oct '18

Ivailo Hartarsky (ENS, France) Titolo: Bootstrap percolation : subcritical universality class and oriented percolation Mercoledi' 24 Ottobre 2018 ORE 16:00 Dipartimento di Matematica e Fisica Universita' degli Studi Roma Tre Largo San Leonardo Murialdo,1 - Pal.C - Aula 211 Abstract Bootstrap percolation is a wide class of deterministic monotone cellular automata with random initial state closely related to several other statistical physics models such as the kinetically constrained spin models for the spin glass transition. There are three `universality classes' of bootstrap percolation in two dimensions. Of them the `subcritical' ones those exhibiting a non-trivial phase transition are by far the most poorly understood. In this work we develop a first approach for studying them. We will start with a gentle introduction to the field and its universality picture to provide the necessary background. We will then introduce the main new notion of critical density and state our main result. We will then illustrate the method by applications to concrete examples yielding new and old results in the area. The approach establishes and exploits a tight connection with a new generalization of classical oriented percolation, whose further study will have a direct impact on bootstrap percolation. The talk will be based on the preprint arxiv:1806.11405.

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Assegno di ricerca presso Politecnico di Milano
by Alessandra Menafoglio 16 Oct '18

16 Oct '18

Il Dipartimento di Matematica del Politecnico di Milano ha bandito un assegno di ricerca di 12 mesi descritto in dettaglio al link https://www.polimi.it/index.php?id=3971 <https://www.polimi.it/index.php?id=3971&tx_wfqbe_pi1%5bID%5d=7923> &tx_wfqbe_pi1%5bID%5d=7923 sul tema Modellazione statistica e numerica di trasporto di sedimenti in bacini montani nell'ambito della partecipazione del laboratorio MOX al progetto della Fondazione CARIPLO SMART-SED. Eventuali interessati possono contattare <mailto:luca.bonaventura@polimi.it> luca.bonaventura(a)polimi.it <mailto:alessandra.menafoglio@polimi.it> alessandra.menafoglio(a)polimi.it per maggiori informazioni. La scadenza del bando è il 25 ottobre 2018 e la prevista data per la presa di servizio il primo dicembre 2018. Grazie in anticipo per la diffusione a tutti i potenziali interessati. Alessandra Menafoglio -- Alessandra Menafoglio MOX - Dept. of Mathematics Politecnico di Milano Piazza Leonardo da Vinci, 32, 20133, Milan Italy Phone: +39 02 2399 4642 Email: <mailto:alessandra.menafoglio@polimi.it> alessandra.menafoglio(a)polimi.it

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Seminario di Clement Erignoux il 23/10/18 a Roma Tre
by Pietro Caputo 16 Oct '18

16 Oct '18

Clement Erignoux Universita' di Roma Tre Titolo: Hydrodynamics for a non-ergodic activated exclusion process Martedi' 23 Ottobre 2018 ORE 14:30 Dipartimento di Matematica e Fisica Universita' degli Studi Roma Tre Largo San Leonardo Murialdo,1 - Pal.C Abstract The Entropy Method introduced by Guo, Papanicolaou and Varadhan (1988) has been used with great sucess to derive the scaling hydrodynamic behavior of wide ranges of conserved lattice gases (CLG). It requires to estimate the entropy of the measure of the studied process w.r.t. some nice, usually product, measure. In this talk, I will present an exclusion model inspired by a model introduced by Goncalves, Landim, Toninelli (2008), with a dynamical constraint, where a particle at site x can only jump to x+delta iff site x-delta (delta=pm1) is occupied as well. I will give some insight on the different microscopic and macroscopic situations that can occur for this model, and briefly describe the steps to derive the hydrodynamic limit for this model by adapting the Entropy Method to non-product reference measures. I will also expand on the challenges and question raised by this model and on some of its nice mapping features. Joint work with O. Blondel, M. Sasada, and M. Simon.

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Fwd: avviso seminari di Matematica proff. Paolo Butta, Michela Ottobre e Boguslaw Zegarlinski (18.10.2018)
by Franco Flandoli 13 Oct '18

13 Oct '18

SEMINARI DI MATEMATICA Giovedì 18 ottobre 2018 *Scuola Normale Superiore* Pisa Sala Conferenze, Collegio Puteano si terranno i seguenti seminari: 14:30 *Paolo Buttà* ( Università di Roma "La Sapienza"), *“On the large deviations of interface motions in statistical mechanics models”* *Abstract:* *In this talk, I consider the sharp interface limit of the action functional associated to either the Glauber dynamics for Ising systems with Kac potentials or the Glauber+Kawasaki process. The corresponding limit functionals provide, in the sense of large deviations theory, the probability of deviations from the mean curvature flow. I discuss, in the case of smooth interfaces, the derivation of these functionals, for which explicit formulae of the mobility and transport coefficients are given. This is joint work with L. Bertini and A. Pisante.* 15:20 *Michela Ottobre* (Heriot-Watt University, Edimburgh), *“Beyond the Hoermander condition”* *Abstract:* *The study of diffusion processes of elliptic and hypoelliptic type has by now produced a fully-fledged theory, involving several branches of mathematics: stochastic analysis, analysis of differential operators, (sub-)Riemannian geometry and control theory, just to mention the main players. One of the key steps in the development of such a theory has been the seminal paper of Hoermander and a large body of work has been dedicated for over 40 years to the study of diffusion processes under the Hoermander Condition (HC), which is a sufficient condition for hypoellipticity. We propose to study processes that do not, in general, satisfy the HC. In place of the HC, we wish to enforce a weaker condition, the so-called UFG condition, introduced by Kusuoka and Strook with probabilistic motivations, and, independently, by Sussman, Hermann and Lobry, this time in the field of control theory. In particular, Kusuoka and Strook showed that it is still possible to build a solid PDE theory for diffusion semigroups even in absence of the Hoermander condition. We will present new results on the geometry and long time behaviour of diffusion semigroups that do not satisfy the Hoermander condition. Our interest in UFG diffusions stems from the observation that they constitute a large class of SDEs which exhibit multiple invariant measures and such that it is possible to determine in a systematic way the basin of attraction of each equilibrium state. This is a joint work with P. Dobson (Maxwell Institute), T. Cass and D. Crisan (Imperial College).* 16:10 *Boguslaw Zegarlinski* (Imperial College London), *“Hypoelliptic diffusion in noncommutative setup”* *Abstract:* *I will review results and problems concerning hypoelliptic diffusion and coercive (Poincare and Log-Sobolev) inequalities.* Tutti gli interessati sono invitati a partecipare. Classe di Scienze Valeria Giuliani Scuola Normale Superiore Servizio alla Didattica e Allievi tel. 050 509260 Piazza dei Cavalieri, 7 56126 Pisa E-mail: valeria.giuliani(a)sns.it E-mail: classi(a)sns.it

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Politecnico di Milano - Seminario Iacopini
by Laura Maria Sangalli 12 Oct '18

12 Oct '18

Si avvisa che in data 08-11-2018, alle ore 11:30 precise, presso l'Aula Seminari "F. Saleri" VI piano, Dipartimento di Matematica, Politecnico di Milano, si svolgerà il seguente seminario: Relatore Matteo Iacopini, Università Ca’ Foscari Venezia Titolo Bayesian Dynamic Tensor Regression Sommario Multidimensional arrays (i.e. tensors) of data are becoming increasingly available and call for suitable econometric tools. We propose a new dynamic linear regression model for tensor-valued response variables and covariates that encompasses some well known multivariate models such as SUR, VAR, VECM, panel VAR and matrix regression models as special cases. For dealing with the over-parametrization and over-fitting issues due to the curse of dimensionality, we exploit a suitable parametrization based on the parallel factor (PARAFAC) decomposition which enables to achieve both parameter parsimony and to incorporate sparsity effects. Our contribution is twofold: first, we provide an extension of multivariate econometric models to account for both tensor-variate response and covariates; second, we show the effectiveness of proposed methodology in defining an autoregressive process for time-varying real economic networks. Inference is carried out in the Bayesian framework combined with Monte Carlo Markov Chain (MCMC). We show the efficiency of the MCMC procedure on simulated datasets, with different size of the response and independent variables, proving computational efficiency even with high-dimensions of the parameter space. Finally, we apply the model for studying the temporal evolution of real economic networks. Tutti gli interessati sono invitati a partecipare. Cordiali saluti, Laura Sangalli -- Laura Maria Sangalli MOX - Dipartimento di Matematica Politecnico di Milano Piazza Leonardo da Vinci 32 20133 Milano - Italy tel: +39 02 2399 4554 fax: +39 02 2399 4568 email: laura.sangalli(a)polimi.it<mailto:laura.sangalli@polimi.it> url: http://mox.polimi.it/~sangalli

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Seminario VAN DER PAS
by Matteo Ruggiero 12 Oct '18

12 Oct '18

STATISTICS SEMINARS @ COLLEGIO CARLO ALBERTO Venerdì 19 Ottobre 2018, alle ore 12:00, presso il nuovo edificio del Collegio Carlo Alberto, in Piazza Arbarello 8, Torino, si terrà il seguente seminario: ------------------------------------------------ Stephanie VAN DER PAS (Leiden University) POSTERIOR CONCENTRATION FOR BAYESIAN REGRESSION TREES AND THEIR ENSEMBLES Since their inception in the 1980's, regression trees have been one of the more widely used nonparametric prediction methods. Tree-structured methods yield a histogram reconstruction of the regression surface, where the bins correspond to terminal nodes of recursive partitioning. Trees are powerful, yet susceptible to overfitting. Strategies against overfitting have traditionally relied on pruning greedily grown trees. The Bayesian framework offers an alternative remedy against overfitting through priors. Roughly speaking, a good prior charges smaller trees where overfitting does not occur. In this paper, we take a step towards understanding why/when do Bayesian trees and their ensembles not overfit. We study the speed at which the posterior concentrates around the true smooth regression function. We propose a spike-and-tree variant of the popular Bayesian CART prior and establish new theoretical results showing that regression trees (and their ensembles) (a) are capable of recovering smooth regression surfaces, achieving optimal rates up to a log factor, (b) can adapt to the unknown level of smoothness and (c) can perform effective dimension reduction. These results provide a piece of missing theoretical evidence explaining why Bayesian trees (and additive variants thereof) have worked so well in practice. ------------------------------------------------ Tutti gli interessati sono invitati a partecipare. Il seminario è organizzato dalla "de Castro" Statistics Initiative (www.carloalberto.org/stats) in collaborazione con il Collegio Carlo Alberto. Cordiali saluti, Matteo Ruggiero --- Matteo Ruggiero University of Torino and Collegio Carlo Alberto www.matteoruggiero.it

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