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Webinar in Statistics MATTHIAS LOFFLER
by Pierpaolo De Blasi 23 Apr '21

23 Apr '21

WEBINARS IN STATISTICS @ COLLEGIO CARLO ALBERTO <https://www.carloalberto.org/events/category/seminars/seminars-in-statistic…> Venerdi 30 Aprile 2021, alle ore 12.00, si terrà il seguente webinar: ------------------------------------------------ Speaker: *Matthias Loffler *(ETH Zurich) Title: *Optimality of Spectral Clustering in the Gaussian Mixture Model* Zoom link: https://us02web.zoom.us/j/81943504316?pwd=anlwTXpXSkU4R1ZsMjMxVEo5NHcwQT09 Meeting ID: 819 4350 4316 Passcode: 355115 Abstract: Spectral clustering is one of the most popular algorithms to group high dimensional data. It is easy to implement and computationally efficient. Despite its popularity and successful applications, its theoretical properties have not been fully understood. We show that spectral clustering is minimax optimal in the Gaussian Mixture Model with isotropic covariance matrix, when the number of clusters is fixed and the signal-to-noise ratio is large enough. Spectral gap conditions are widely assumed in the literature to analyze spectral clustering. On the contrary, we show that these conditions are not needed. ------------------------------------------------ Il webinar è organizzato dalla "de Castro" Statistics Initiative www.carloalberto.org/stats Cordiali saluti, Pierpaolo De Blasi --- University of Torino & Collegio Carlo Alberto carloalberto.org/pdeblasi <https://sites.google.com/a/carloalberto.org/pdeblasi/>

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Post-doc position available at the University of Oslo, Norway. Deadline approaching!
by Valeria Vitelli 22 Apr '21

22 Apr '21

*A three-years postdoc position in Biostatistics is offered at the Oslo Centre for Biostatistics and Epidemiology (OCBE), University of Oslo, Norway. * The position is funded under the* SCIENTIA FELLOWS* program, a transnational research fellowship programme in the field of Health Life Sciences at the University of Oslo, funded by the EU Horizon 2020 under the Maria Skłodowska-Curie scheme. *More information available here:* https://www.med.uio.no/imb/english/research/groups/statistics-high-dimensio… *Hosts: *Valeria Vitelli ( https://www.med.uio.no/imb/english/people/aca/valeriv/) and David Swanson ( https://sojourningnorth.github.io/) *Deadline for submission: May 11th, 2021* *Call, detailed information and how to apply:* (thematic area: "biostatistics") https://www.med.uio.no/english/research/scientia-fellows/apply/ *If you are interested in the position, please contact the hosts above as soon as possible! *In order to apply for the position, you have to submit a research proposal (and other documents as specified in the call) by May 11th, 2021. The position will be at the Oslo Centre for Biostatistics and Epidemiology (OCBE), Faculty of Medicine, University of Oslo ( https://www.med.uio.no/imb/english/research/centres/ocbe/). *Salary: 526 000 NOK/year (roughly 52K EUR/year)* *Eligibility:* - You possess a PhD degree (at the latest by 1 July 2021) in statistics, biostatistics, mathematics, computer science or other related disciplines with a documented competence in statistics, biostatistics or mathematics. - You have not been resident in Norway for more than 12 months in the last 3 years. -- Valeria Vitelli Oslo Center for Biostatistics and Epidemiology, Department of Biostatistics, University of Oslo, Norway mailto: valeria.vitelli(a)medisin.uio.no

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Summer School - Stochastic Models and Complex Systems
by Barbara Martinucci 22 Apr '21

22 Apr '21

Dear All, We are glad to announce the forthcoming Summer School, entitled *"Stochastic Models and Complex Systems"*, that will be held online in the period June 10th - July 7th, 2021. The Summer School is open to PhD students, postdoc and young researchers interested in the treated topics. It will feature mini-courses of plenary speakers, exercise sessions and students' talks. *Plenary courses *include: - *Enrico Scalas* (University of Sussex) "*A gentle introduction to combinatorial stochastic processes (with applications to Physics, Finance and Economics)*", 16 hours; - *Yuliia Mishura* (Taras Shevchenko National University of Kyiv) "*Statistics of fractional models*", 8 hours; - *Jorge Navarro* (University of Murcia) "*Selected Topics on Distorted models and applications*", 6 hours. An outline of the event, including the themes covered, is already available on the website http://dipmat2.unisa.it/iniziative/smocs2020/School.html The students willing to apply for the Summer School are invited to fill the registration form available on the website. The participation is free but the registration is mandatory. Only the first 50 registration will be admitted. For any question, send an email to: smocs2021(a)gmail.com Do not hesitate to CIRCULATE this announcement to your colleagues and students. Best regards, the Organizing Committee

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2nd Spring Colloquium on Probability and Finance
by Claudio Fontana 22 Apr '21

22 Apr '21

Dear all, We would like to bring to your attention the following virtual workshop: /2ND SPRING COLLOQUIUM ON PROBABILITY AND FINANCE - /29 APRIL 2021, 9.00 - 13.00, ONLINE University of Padova, Department of Mathematics "Tullio Levi-Civita" The second edition of the Spring Colloquium on Probability and Finance will bring together researchers working in stochastic analysis and mathematical finance. The workshop will feature five invited talks and attendance is open. To attend the Colloquium, please register by sending an e-mail to the organisers (Giorgia Callegaro and Claudio Fontana). _SPEAKERS_: • René AID (Paris Dauphine Universty, FR) • Luciano CAMPI (University of Milan, IT) • Alessandro GNOATTO (University of Verona, IT) • Antoine JACQUIER (Imperial College London, UK) • Barbara PACCHIAROTTI (University of Rome "Tor Vergata", IT) Best regards, Giorgia Callegaro and Claudio Fontana

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Pisa Online Seminars - Constanza Rojas-Molina (Tuesday, April 27 at 16:00)
by Giacomo Filippo Di Gesu 21 Apr '21

21 Apr '21

Dear colleagues, I would like to invite you to the following online seminar organized by the Probability group of the University of Pisa. The talk will be accessible under the link Click here to join<https://teams.microsoft.com/l/meetup-join/19:af3d635091e049579e555a84219ab3…"Tid":"c7456b31-a220-47f5-be52-473828670aa1","Oid":"dfd1e5f6-331d-43e0-a180-4bb6ce727fb7"}> Best regards, Giacomo Tuesday, April 27, 16:00 Speaker: Constanza Rojas-Molina (CY Cergy Paris Université) Title: (Fractional) random Schrödinger operators, integrated density of states and localization Abstract: We consider the continuous Schrödinger operator - d^2/d^x^2 + B’(x) on the interval [0,L] where the potential B’ is a white noise. We study the entire spectrum of this operator in the large L limit. We prove the joint convergence of the eigenvalues and of the eigenvectors and describe the limiting shape of the eigenvectors for all energies. When the energy is much smaller than L, we find that we are in the localized phase and the eigenvalues are distributed as a Poisson point process. The transition towards delocalization holds for large eigenvalues of order L. In this regime, we show the convergence at the level of operators. The limiting operator in the delocalized phase is acting on R^2-valued functions and is of the form ``J \partial_t + 2*2 noise matrix'' (where J is the matrix ((0, -1)(1, 0))), a form appearing as a conjecture by Edelman Sutton (2006) for limiting random matrices. Joint works with Cyril Labbé. ************************ Giacomo Di Gesù Dipartimento di Matematica Università di Pisa Largo Bruno Pontecorvo 5 56127 - Pisa, Italy giacomo.digesu(a)unipi.it<mailto:giacomo.digesu@unipi.it> https://sites.google.com/site/giacomodigesu/

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(PMS)^2 online talk: Zdzislaw Brzezniak, Monday April 26 at 17:30
by Mario Maurelli 21 Apr '21

21 Apr '21

Dear colleagues, We are happy to announce the following online talk: Speaker: *Zdzislaw Brzezniak* (University of York, UK) Title: *The stochastic Strichartz estimates and stochastic nonlinear Schrödinger equations driven by Levy noise* Date and time: *Monday April 26, 17:30-18:30 (Rome time zone)* Abstract: see below Zoom link: https://us02web.zoom.us/j/87131794820?pwd=R3l0VEtpZXNzUmQ1bnlnbWhBUm5XQT09 Meeting ID: 871 3179 4820 Passcode: 5yFGwK This talk is the first of the *(PMS)^2: Pavia-Milano Seminar series on Probability and Mathematical Statistics* organized jointly by the universities Milano-Bicocca, Pavia, Milano-Politecnico and Milano-Statale. The series will run approximately every fortnight and, for the moment, will be held online. Participation is free and welcome! (though limited to 100 participants for technical reasons) Best regards The organizers (Mario Maurelli, Carlo Orrieri, Maurizia Rossi, Margherita Zanella) Abstract: We establish a new version of the stochastic Strichartz estimate for the stochastic convolution driven by jump noise which we apply to the stochastic nonlinear Schrodinger equation with nonlinear multiplicative jump noise in the Marcus canonical form. With the help of the deterministic Strichartz estimates, we prove the existence and uniqueness of a global solution to stochastic nonlinear Schrodinger equation in $L^2(R^n)$ with either focusing or defocusing nonlinearity in the full subcritical range of exponents as in the deterministic case. This talk will be based on a joint paper with Wei Liu and Jiahui Zhu.

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Seminar Pierre Alquier @Bocconi - April 22
by Giacomo Zanella 21 Apr '21

21 Apr '21

A reminder of the following BIDSA webinar (link <https://www.bidsa.unibocconi.eu/wps/wcm/connect/site/bidsa/home/news_events…> ): Date: Thursday, April 22, h14:00 (Italy time) Speaker: Pierre Alquier (RIKEN) Title: Robust Estimation via M.M.D. Minimization Abstract: In this talk, I will study the properties of parametric estimators based on the Maximum Mean Discrepancy (MMD) defined by Briol et al. (2019). In a first time, I will show that these estimators are universal in the i.i.d setting: even in case of misspecification, they converge to the best approximation of the distribution of the data in the model, without ANY assumption on this model. This leads to very strong robustness properties. In a second time,I will show that these results remain valid when the data is not independent, but satisfy instead a weak-dependence condition. This condition is based on a new dependence coefficient, which is itself defined thanks to the MMD. I will show through examples that this new notion of dependence is actually quite general. Reference: This talk is based on the following papers and softwares, with Badr-Eddine Chérief Abdellatif (Oxford University), Mathieu Gerber(University of Bristol), Jean-David Fermanian (ENSAE Paris) and Alexis Derumigny (University of Twente): http://arxiv.org/abs/1912.05737 http://proceedings.mlr.press/v118/cherief-abdellatif20a.html http://arxiv.org/abs/2006.00840 https://arxiv.org/abs/2010.00408 https://cran.r-project.org/web/packages/MMDCopula/ The webinar will be on zoom at: https://zoom.us/j/95795747882 Meeting ID: 957 9574 7882 Passcode: 025765 Kind regards, Giacomo Zanella

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(Reminder) Seminar Thursday 22 - Optimal constrained and unconstrained subgraph structures (prof. Clara Stegehuis)
by Gianmarco Bet 21 Apr '21

21 Apr '21

Dear colleagues, This is a reminder that tomorrow (Thursday 22) at 14:30, prof. Clara Stegehuis (Twente University) will give a virtual seminar “in Florence”, to which you are all invited. You can find title and abstract below this message. The seminar will be on Zoom. You can find the information to join below. If you know of someone who might be interested and is not subscribed to the random mailing list, please do not hesitate to forward this announcement to them. Kind regards, Gianmarco Topic: Clara Stegehuis - Optimal constrained and unconstrained subgraph structures Time: Apr 22, 2021 02:30 PM Rome Join Zoom Meeting https://us02web.zoom.us/j/85651690146?pwd=ZnRCbGR6OUlxM2J4RldJd2R1aVE3Zz09 <https://us02web.zoom.us/j/85651690146?pwd=ZnRCbGR6OUlxM2J4RldJd2R1aVE3Zz09> Meeting ID: 856 5169 0146 Passcode: 770134 Title: Optimal constrained and unconstrained subgraph structures Abstract: Subgraphs contain important information about network structures and their functions. We investigate the presence of subgraphs in a random graph model with infinite-variance degrees. We introduce an optimization problem which identifies the dominant structure of any given subgraph. The unique optimizer describes the degrees of the vertices that together span the most likely subgraph and allows us to count and characterize the asymptotic number of subgraphs in a simple manner. We then show that this optimization problem easily extends to investigating other random network structures, such as clustering, which expresses the probability that two neighbors of a vertex are connected. The optimization problem is able to find the behavior of network subgraphs in a wide class of random graph models. ---------------------------------------------------------------------- Gianmarco Bet (he/him) Junior researcher https://gianmarco.bet Phone: (+39) 055 2751491 Department of Mathematics and Informatics "U. Dini" University of Florence Viale Morgagni, 65 50134 Firenze, Italy Office 64 ----------------------------------------------------------------------

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Online seminar Svaluto-Ferro
by matteo.burzoni＠unimi.it 20 Apr '21

20 Apr '21

Dear colleagues, it is our pleasure to invite you to the following online seminar: Zoom link (see also details below): <https://us02web.zoom.us/j/88398874167?pwd=YkRzdlNYWjVjUlc3T294ZjZuVHNSdz09> https://us02web.zoom.us/j/88398874167?pwd=YkRzdlNYWjVjUlc3T294ZjZuVHNSdz09 Speaker: <https://homepage.univie.ac.at/sara.svaluto-ferro/> Sara Svaluto-Ferro (University of Vienna) Title: From signature-based models to affine and polynomial processes and back. Time: Tuesday, April 27, 4PM (Italian time) Abstract: Modern universal classes of dynamic processes, based on neural networks or signature methods, have recently entered the field of stochastic modeling, in particular in Mathematical Finance. This has opened the door to more data-driven and thus more robust model selection mechanisms, while principles like no arbitrage still apply. We analyze here different types of signature models. In the first part, we focus on models based on the signature of a supporting process, which can range from a Brownian motion, to a multidimensional Levy-process, to a general multidimensional tractable stochastic process, to the times series corresponding to some liquid objects on the market. We also present methods how to fit these models to data. In the second part we focus on signature SDEs, i.e. (possibly Lévy driven) SDEs whose characteristics are linear functions of the process signature. We show how these new models can be embedded in the framework of affine and polynomial processes, which have been - due to their tractability - the dominating process class prior to the new era of highly overparametrized dynamic models. We show that generic classes of diffusion models can be described in terms of a signature SDEs. This allows to get power series expansions for expected values of analytic functions of the process' marginals. The talk is based on joint works with Christa Cuchiero, Guido Gazzani, Francesca Primavera and Josef Teichmann. Zoom meeting details: meeting ID: 883 9887 4167 Passcode: mVJ6SR Best, Matteo Burzoni

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New deadline for BISP12 - Twelfth Workshop on Bayesian Inference in Stochastic Processes
by elisa varini 20 Apr '21

20 Apr '21

Having received some late submission requests, we decided to reopen the call for contributed papers until 25 April 2021. It is possible to submit abstracts (using the templates in the website) at https://bisp12.imati.cnr.it/ In the meantime, we have completed the list of invited speakers (all junior ones) and we are going to contact senior researchers who will serve as discussants. The speakers will be: • Atilla Ay (George Washington University, USA) • Clara Grazian (University of New South Wales, Australia) • Andrew Holbrook (University of California, Los Angeles, USA) • Kaoru Irie (University of Tokyo, Japan) • Roi Naveiro (CSIC-ICMAT, Spain) • Giovanni Rebaudo (University of Texas at Austin, USA) • Claudia Solis-Lemus (University of Wisconsin-Madison, USA) • Stéphanie Van Der Pas (Amsterdam UMC, The Netherlands) • Andi Wang (University of Bristol, UK) • Paul Wu (Queensland University of Technology, Australia) The titles of their contributions are available on the website. It is also possible to register (free of charge) on the same website to attend the workshop on 27-28 May (afternoons, Central European Summer Time). Elisa Varini and Fabrizio Ruggeri Chairs, Organising and Scientific Committees

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