Past talks

Felipe Linares - IMPA

November 26 at 4:15pm

Title: On long time behavior of solutions of the Schrödinger-Korteweg-de Vries system

Abstract: In this lecture we will be concerned with the decay of long time solutions of the initial value problem associated with the Schrödinger-Korteweg-de Vries system. We use recent techniques in order to show that solutions of this system decay to zero in the energy space. Our result is independent of the integrability of the equations involved and it does not require any size assumptions.

Video: https://drive.google.com/file/d/1CSvHgceMv3ZrRwe0YgQ6l_wnTRrvhLvH/view

Jacson Simsen - UNIFEI

November 12 at 4:15pm

Title: A generalization of Baras’ Theorem and application for nonautonomous coupled inclusions

Abstract: In this talk we shall see a compactness result which is a generalization of Baras’ Theorem for the case when the main operator is time-dependent and we will give an application for nonautonomous coupled inclusions, proving that these multivalued problems under certain conditions define exact generalized processes.

video: https://drive.google.com/file/d/1YR1SdUeVxiZP2d3FE5WdQduVojzAiDlt/view

Rosa Pardo - U. Complutense de Madrid

October 29 at 4:15pm

Title: On generalized subcritical elliptic problems with non-power nonlinearity

Abstract: See pdf file below :-)

Video: https://drive.google.com/file/d/1Hl2zz2mqL5o0QE4zS-5bkBw6jIe1tW-Y/view

Everaldo M. Bonotto - ICMC-USP

October 15 at 4:15pm

Title: Lyapunov stability in impulsive dynamical systems

Abstract: In this talk, we establish necessary and sufficient conditions to obtain uniform and orbital stability for a special class of sets in the framework of impulsive dynamical systems.

Video: https://drive.google.com/file/d/1KmC7fj6omtv0FD08VAsJC1pJ7pd8Orur/view

Jaime Angulo Pava - IME-USP

October 01 at 4:15pm

Title: Wave dynamics for evolution equations on metric graphs

Abstract: In this talk we shed new light on the mathematical studies of nonlinear dispersive evolution equations on metric graphs. This trend has been mainly motivated by the demand of reliable mathematical models for different phenomena in branched systems which, in meso- or nano-scales, resemble a thin neighborhood of a graph, such as Josephson junction networks, electric circuits, unidirectional shallow water flow in a network, blood pressure waves in large arteries, or nerve impulses in complex arrays of neurons, just to mention a few examples. Our dynamic problems here will be essentially the following: Schrödinger operators on metric graphs, the existence of solitons profiles, (in)stability criterium, and the Cauchy problem. In particular we study the instability of kink-soliton profiles for the sine-Gordon model on Y-metric graph.

The arguments presented in this lecture have prospects for the study of the (in)stability of soliton-profiles solutions of other nonlinear evolution equations on branched systems.

Video: https://drive.google.com/file/d/1248RXajpKN3f2fvqZTa9MnjSvDM0JUQC/view

Flank D. M. Bezerra - Universidade Federal da Paraíba

September 10 at 4:15pm

Title: A equação $d^3u/dt^3+Au=0$

Abstract: Nesta palestra apresentaremos resultados relacionados à equação $d^3u/dt^3+Au=0$ em espaços de Banach onde $A$ é um operador linear não necessariamente limitado.

Video: https://drive.google.com/file/d/1NjjT9cvgZvL5EYt4eQvcGDcnTD0tqq0x/view

Carlos Rocha - Instituto Superior Técnico de Lisboa

August 27 at 4:15pm

Title: Meanders, zero numbers and the cell structure of Sturm global attractors

Abstract: In this talk we overview recent results on the geometric and combinatorial characterization of global attractors of semiflows generated by scalar semilinear partial parabolic differential equations under Neumann boundary conditions. In particular, we review a nonlinear Sturm-Liouville property and a minimax property of the boundary neighbors of any specific unstable equilibrium. These properties allow the identification of equilibria on the cell boundary of any chosen unstable equilibrium. This is a joint work with B. Fiedler.

Video: https://drive.google.com/file/d/1uUEHppQfbzxD2eh-N21NIq24Pwy8cfeq/view

Jaqueline Godoy Mesquita - UnB

July 30 at 4:15pm

Title: Neutral functional differential equations with state-dependent delays: an overview and recent results

Abstract: In this talk, we provide a basic overview of neutral functional differential equations with state-depedent delays and we investigate a principle of linearized instability for these equations. Also, we introduce a more general class of equations called "measure neutral functional differential equations with state-dependent delays", and discuss some properties and results for these equations.

Video: https://drive.google.com/file/d/1e9MkYKoJ36lVdjswjxiDDXf3oaB9rB7l/view

Anibal Rodríguez Bernal - U. Complutense de Madrid

July 16 at 4:15pm

Title: Nonlinear-like behavior in the linear heat equation in R^{N}

Abstract: We consider the linear heat equation in R^{N} for some classes of initial data which are very large at infinity. We reveal a mechanism of “mass moving from infinity” that produces nonlinear-like behavior in the solutions: finite time blow-up and arbitrarily prescribed oscillatory behavior for some solutions which exists globally.

In the case of finite time blow-up we determine the blow-up time and the blow-up set (the complement of a convex set) and given any closed convex set we can construct a solution that blows up in a given time precisely in the complementary set.

If time allows I’ll give results showing an optimal Frechet space of large functions in which the linear heat equation defines a suitable analytic semigroup of global solutions.

This is a joint work with J.C. Robinson (U.Warwick, UK).

Video: https://drive.google.com/file/d/18qfsllduTAIIZ7kHTqhHjiARB8Nmhy62/view

Simone Bruschi - UnB/George Washington University

July 02 at 4:15pm

Title: Price formation models

Abstract: We present the price formation model introduced by J.-M. Lasry and P.-L. Lions and the known results for this model. We also discuss modified versions of the model to incorporate the impact of the evolution of prices in market behavior.

Video: https://drive.google.com/file/d/1FYX3h-dwxCU3QsY06az90oVfhIbgZES3/view

Sergio Oliva - IME-USP

June 18 at 4:15pm

Title: Spatiotemporal epidemic modeling of COVID19 using Mobile phone data

Abstract: We present the recent studies of our group of the Applied Math Department addressing the COVID19 pandemic. Our group has been working since March, collaborating and exchanging results with several groups. These collaborative efforts have produced excellent scenarios from several points of view. We focus our attention on the contribution of mobile phone geolocation data in predicting human movement and thus enhancing the usual epidemic models, such as SI and SEIR. These results are being used by the state government as input to its decisions.

Video: https://drive.google.com/file/d/19jEETO10-QSaHpg7eWiLNJatpEIwChtN/view

Severino Horácio - UFCG

Data: 04/06 Hora: 16h15

Título: Uma Adaptação do Modelo Epidemiológico SIR para estudar a Dinâmica de Disseminação da COVID-19 no Brasil, na Paraíba e em Campina Grande

Resumo: Neste trabalho, adaptamos o bem conhecido e testado modelo epidemiológico SIR, proposto por Kermack e Mckendrick (1927), para estudar a dinâmica de disseminação da COVID-19 no Brasil, bem como no estado da Paraíba e na cidade de Campina Grande-PB. Validamos o nosso modelo epidemiológico com a comparação com dados oficiais dos números de casos confirmados, de recuperados e de óbitos devidos à pandemia no Brasil, na Paraíba e em Campina Grande-PB. Obtivemos ótimos ajustes ao permitirmos a variação temporal da taxa de contágio, o que reflete a maior ou menor adesão do isolamento social pelas populações envolvidas. Fazemos também previsões epidemiológicas para os próximos dias e esperamos que este estudo de dinâmica epidemiológica contribua para conscientizar os gestores das políticas de saúde pública sobre a necessidade de reforçarem a aplicação das medidas de distanciamento/isolamento social para que o máximo de segurança possível para população seja obtido.

Vídeo: https://1drv.ms/v/s!ArjEJxAATvnSibM8hoo6RPrsWPp6ng?e=arme0S