Speaker: Professor Julio López

Instituto de Ciencias Básicas, Universidad Diego Portales, Santiago, Chile

Date:  September 08,  2021 at 09:30 am (Chilean-time)

Title:   Regularized  version of the minimax  probability machine

Abstract: In this talk we present novel second-order cone programming formulations for binary classification, by extending the Minimax Probability Machine (MPM) approach. Inspired by Support Vector Machines, a regularization term is included in the MPM and Minimum Error Minimax Probability Machine methods. This inclusion reduces the risk of obtaining ill-posed estimators, stabilizing the problem, and, therefore, improving the generalization performance. Our approaches are first derived as linear methods, and subsequently extended as kernel-based strategies for nonlinear classification. Experiments on well-known binary classification datasets demonstrate the virtues of the regularized formulations in terms of predictive performance.

A recorded video of the conference is …. ;  the slides can be downloaded  …

Venue: Online via Google Meet: https://meet.google.com/gjq-cwic-udo

A brief biography of the speaker: Julio López is an Associate Professor at the Institute of Basic Sciences, University Diego Portales, Santiago, Chile. He obtained his PhD degree at the University of Chile, in 2009. His research interests include conic programming, convex analysis, algorithms, and machine learning.

Coordinators: Fabián Flores-Bazán (CMM, Universidad de Concepción) and Abderrahim Hantoute (Alicante)

Speaker: Professor Jiri Outrata

Institute of Information Theory and Automation, Czech Academy of Sciences, Prague – Czech Republic

Date:  May 19,  2021 at 10:00 am (Chilean-time)

Title:   On the solution of static contact problems with Coulomb friction via the semismooth Newton method

Abstract: The lecture deals with application of a new Newton-type method to the numerical solution of discrete 3D contact problems with Coulomb friction. This method suits well to the solution of inclusions and the resulting conceptual algorithm exhibits, under appropriate conditions, the local superlinear convergence. After a description of the method a new model for the considered contact problem, amenable to the application of the method, will be presented. The second part of the talk is then devoted to an efficient implementation of the general algorithm and to numerical tests. Throughout the whole lecture, various tools of modern variational analysis will be employed.

A recorded video of the conference is …. ;  the slides can be downloaded  …

Venue: Online via Google Meet: https://meet.google.com/gqt-mpjz-kyt

A brief biography of the speaker: Jiri V. Outrata is a senior researcher in the Czech Academy of Sciences, Prague. He obtained his PhD in 1976 and DrSc (habilitation) in 1991, both from the Czech Academy of Sciences. A part of his career he spent in Germany, at the Universities in Bayreuth and Erlangen. His current research interests concern variational analysis; in particular, generalized differential calculus and its application to equilibrium problems.

Coordinators: Fabián Flores-Bazán (CMM, Universidad de Concepción) and Abderrahim Hantoute (Alicante).

Speaker: Professor Orestes Bueno

Universidad del Pacífico, Lima, Perú

Date:  January 20,  2021 at 10:00 (Chilean-time)

Title:   On the construction of maximal p-cyclically monotone operators

Abstract: In this talk we deal with the construction of explicit examples of maximal p-cyclically maximal monotone operators. To the date, there is only one instance of an explicit example of a maximal 2-cyclically monotone operator that is not maximal monotone. We present several other examples, and a proposal of how such examples can be constructed.

A recorded video of the conference is …. ;  the slides can be downloaded here

Venue: Online via Google Meet  http://meet.google.com/mqh-bgjv-iyb

A brief biography of the speaker: Orestes Bueno is an Associate Professor at Universidad del Pacífico, Lima, Perú. He obtained his PhD at the Instituto de Matemática Pura e Aplicada (IMPA), Brazil, in 2012. His main interests are: Maximal Monotone Operators, Generalized Convexity and Monotonicity, Functional Analysis.

Coordinators: Fabián Flores-Bazán (Universidad de Concepción) and Abderrahim Hantoute (CMM).

Speaker: Professor Wilfredo  Sosa

Graduate Program of Economics, Catholic University of Brasilia,  Brazil

Date:  November 18,  2020 at 10:00

Title: On diametrically maximal sets, maximal premonotone maps and premonotone bifunctions

Abstract: First, we study diametrically maximal sets in the Euclidean space (those which are not properly contained in a set with the same diameter), establishing their main properties. Then, we use these sets for exhibiting an explicit family of maximal premonotone operators. We also establish some relevant properties of maximal premonotone operators, like their local boundedness, and finally we introduce the notion of premonotone bifunctions, presenting a canonical relation between premonotone operators and bifunctions, that extends the well known one, which holds in the monotone case.

A recorded video of the conference is …. ;  the slides can be downloaded here

Venue: Online via Google Meet  meet.google.com/tam-ddhj-psx

A brief biography of the speaker: Wilfredo Sosa es profesor del Programa de Graduados de Economía de la Universidad Católica de Brasilia, Brazil; Egresado de la Universidad de Ingeniería de Lima, Perú. Formado en el IMPA de Rio de Janeiro Brasil. Co-Fundador del IMCA de Lima Peru. Miembro titular de la Academia de Ciencias de Perú. Areas de interés: Optimization theory; Duality theory; Equilibrium theory; Mathematical economy.

Coordinators: Fabián Flores-Bazán (Universidad de Concepción) and Abderrahim Hantoute (CMM)

Speaker: Professor César Gutiérrez

IMUVA (Mathematics Research Institute of the University of Valladolid), Valladolid, Spain

Date:  November 04,  2020 at 10:00

Title: An algebraic view of the smallest strictly monotonic function

Abstract: The talk concerns with one of the most popular functions to derive nonconvex separation results. Complete characterizations for both its level sets and basic properties such as monotonicity and convexity are provided in terms of its parameters. Most of these characterizations work without considering any additional requirement or assumption. Finally, as an application, a vectorial form of the Ekeland variational principle is provided.

A recorded video of the conference is here ;  the slides can be downloaded here

Venue: Online via Google Meet  meet.google.com/tta-bhpu-raa

A brief biography of the speaker: César Gutiérrez (ORCID iD 0000-0002-8223-2088) is Professor at Universidad of Valladolid (Spain) and researcher of the Mathematics Research Institute of the University of Valladolid (IMUVA). He is author of 54 papers on several subjects related to vector and set-valued optimization. Currently, he is Associate Editor of Optimization.

Coordinators: Fabián Flores-Bazán (Universidad de Concepción) and Abderrahim Hantoute (CMM)

Speaker: Doctor Nicolás Hernández

Center for Mathematical Modeling (CMM), Universidad de Chile, Santiago, Chile

Date:  October 07,  2020 at 10:00

Title: Principal-Agent problem in insurance: from discrete-to continuous-time

Abstract: In this talk we present a contracting problem between an insurance buyer and the seller, subject to prevention efforts in the form of self-insurance and self-protection. We start with a static formulation, corresponding to an optimization problem with variational inequality constraint, and extend the main properties of the optimal contract to the continuous-time formulation, corresponding to a stochastic control problem in weak form under non-singular measures.

A recorded video of the conference is here;  the slides can be downloaded here

Venue: Online via Google Meet here

A brief biography of the speaker: Nicolás Hernández is currently a Postdoctoral Researcher at the Center for Mathematical Modeling (CMM), at Universidad de Chile. He obtained his PhD in 2017, as a cotutelle between Université Paris-Dauphine and Universidad de Chile. His research areas of interest are Contract theory, stochastic control, mathematical finance, probability, optimization, game theory.

Coordinators: Fabián Flores-Bazán (Universidad de Concepción) and Abderrahim Hantoute (CMM)

Speaker: Prof. Mohammad Hossein Alizadeh

Institute for Advanced Studies in Basic Sciences (IASBS),
Zanjan, Iran

Date:  September 23, 2020 at 10:00

Title: Sigma-convex functions and Sigma-subdifferentials

Abstract: In this talk we present and study the notion of $\sigma$-subdifferential of a proper function $f$ which contains the Clarke-Rockafellar subdifferential of $f$ under some mild assumptions on $f$.
We show that some well known properties of the convex function, namely Lipschitz property in the interior of its domain, remain valid for the large class of $\sigma$-convex functions.

A recorded video of the conference is here;  the slides can be downloaded here

Venue: Online via Google Meet  meet.google.com/uoq-kifr-nsg

A brief biography of the speaker: Mohammad Hossein Alizadeh is an Assistant
Professor at the Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, Iran. He obtains his Ph.D. from the University the Aegean, Greece, in 2012. He is mainly interested in the following areas:

Monotone and generalized monotone operators, Monotone and generalized monotone
bifunctions, generalized convexity and generalized inverses.

Coordinators: Abderrahim Hantoute (CMM) and Fabián Flores-Bazán (Universidad de Concepción)

Speaker: Prof. Rubén López
University of Tarapacá, Arica, Chile

Date:  August 05, 2020 at 10:00

Title: Epi-convergence, asymptotic analysis and stability in set optimization problems

Abstract: We study the stability of set optimization problems with data that are not necessarily bounded. To do this, we use the well-known notion of epi-convergence coupled with asymptotic tools for set-valued maps. We derive characterizations for this notion that allows us to study the stability of vector and set type solutions by considering variations of the whole data (feasible set and objective map). We extend the notion of total epi-convergence to set-valued maps.

* This work has been supported by Conicyt-Chile under project FONDECYT 1181368

Joint work with Elvira Hérnández, Universidad Nacional de Educación a Distancia, Madrid, Spain

The slides of the conference can be downloaded here

Venue: Online via Google Meet – https://meet.google.com/hgo-zwkr-fvh

A brief biography of the speaker: Prof. Rubén López   is Professor at the University of Tarapacá,  Arica – Chile. He studied at Moscow State University – Mech Math (1996, Russia) and Universidad de Concepción – DIM (2005, Chile). He works on Optimization: asymptotic analysis, variational convergences, stability theory, approximate solutions and well-posedness.

Coordinators: Abderrahim Hantoute (CMM) and Fabián Flores-Bazán (Universidad de Concepción)

Speaker: Prof. Sigifredo Laengle
University of Chile, Santiago, Chile

Date: July 22, 2020 at 10:00

Abstract: The Nash Demand Game (NDG) has been one of the first models (Nash 1953) that has tried to describe the process of negotiation, competition, and cooperation. This model is still subject to active research, in fact, it maintains a set of open questions regarding how agents optimally select their decisions and how they face uncertainty. However, the agents act rather guided by chance and necessity, with a Darwinian flavor. Satisfying, instead of optimising. The Viability Theory (VT) has this approach. Therefore, we investigate the NDG under this point of view. In particular, we ask ourselves two questions: if there are decisions in the NDG that ensure viability and if this set also contains Pareto and equilibrium strategies. Thus, carrying out the work, we find that the answers to both questions are not only affirmative, but that we also advance in characterising viable NDGs. In particular, we conclude that a certain type of NDGs ensures viability and equilibrium. Many interesting questions originate from this initial work. For example, is it possible to fully characterise the NDG by imposing viability conditions? Under what conditions does viability require cooperation? Is extreme polarisation viable?

The slides of the conference can be downloaded here

Venue: Online via Google Meet – meet.google.com/jhb-umew-kwp

A brief biography of the speaker: Prof. Sigifredo Laengle   is an Associate Professor at the University of Chile since 2007. He received his PhD in Germany working on the theoretical problem of the value of information in organisations. He has published articles that articulate phenomena of strategic interaction, and optimisation.

Coordinators: Abderrahim Hantoute and Fabián Flores-Bazán (Universidad de Concepción)