Associate Professor
Department of Mathematics
Universidade Federal da Paraíba · UFPB
araujo@mat.ufpb.br
I am currently based in João Pessoa, Paraíba, Brazil, working in the Department of Mathematics at the Universidade Federal da Paraíba. My research focuses on developing geometric and analytical techniques for understanding partial differential equations (PDEs) and free boundary problems. Specifically, we aim to derive precise regularity (smoothness) estimates for the solutions and their free boundaries. Such regularity is critical not only for ensuring stability and accuracy in numerical simulations but also for understanding the behavior of these models in real-world applications. Free boundary problems are particularly intriguing because they involve regions—called free boundaries—that evolve dynamically and are not predetermined, as with the changing interface between ice and water. My recent work has focused on degenerate PDEs, where the diffusion properties of the governing operators change along these free boundaries, revealing rich and complex free boundaries that require careful mathematical investigation.
These lecture notes serve as an introduction to the analysis of infinity harmonic functions, a subject that has significantly matured in recent years within the field of nonlinear partial differential equations. They are based on the minicourses we taught online during the pandemic at the Universidade Federal da Paraíba (João Pessoa, Brazil) and at the 24th Brazilian Mathematical Colloquium in IMPA (Rio de Janeiro, Brazil) in July 2023. Shorter versions of these lectures were previously delivered by José Miguel Urbano, the second author, at the Universidade Federal do Ceará (Fortaleza, Brazil) in the (southern hemisphere) Summer of 2013, at Aalto University (Helsinki, Finland) in the (northern hemisphere) Spring of 2013 and at KAUST (Thuwal, Saudi Arabia) early in 2017, and by the first author at the Universidade Federal do Rio de Janeiro (Rio de Janeiro, Brazil) in the (southern hemisphere) Summer of 2020
We warmly invite students of all levels and disciplines related to mathematics to reach out to us regarding research projects centered around introductory topics in the analysis of differential equations, functional analysis, and measure theory, whether you are an undergraduate, master's, or Ph.D. We strongly encourage girls to join our research group, as we are committed to promoting inclusivity and gender equality in scientific research.
Rafael Ramos Costa, Ph.D. student (co-advisor, UFRGS)
Diego dos Santos, Ph.D. student
Aureliana Tavares, M.S. student
Renato de Andrade, Undergrad student
Felipe de Andrade, Undergrad student
Lucas Pontes, Undergrad student
Francelina Júlia da Silva, Highschool student
Leonardo Henrique Tavares, Highschool student
Aelson Sobral, Ph.D. student | 2024
Co-advised by Eduardo Teixeira (University of Central Florida - USA)
Thesis Publications: To appear
Current Position: Post-Doctorate Fellow at KAUST - Saudi Arabia
Ginaldo S. Sá, Ph.D. student | 2023
Co-advised by José Miguel Urbano (KAUST - Saudi Arabia)
Thesis: J. Differential Equations & Calc. Var. Partial Differential Equations (awarded SBM Prize, 2023)
Current Position: Post-Doctorate Fellow at the University of Central Florida
Harish Shrivastava, Post-Doctorate | 2019
INCTMat CNPq fellowship