To understand the meaning of the quotation opening this section, we need to know more about its author. Antônio Maia was a man with humble beginnings. Born in a village in the Northeast part of Brazil, his childhood was summarized by working in all sorts of plantations under the scorching sun of the semiarid climate of the region. At the time, in the 70's, this whole region of Brazil was very poor. In the city where he was born, for example, there were not any hospitals, schools, not even electric energy. At 18 years old, he moved to São Paulo, an emerging city at the time. Arriving here, he moved to a small house, living together with around 10 other people, relatives of his that had moved to the big city earlier. Living with no money in a city like São Paulo was no easy task, so he had to accept any kind of work available, from being a waiter, a construction worker, salesman. This is to say that most of the days of his life were a combination of hard work and tough decisions. Despite that, in the quote, he claimed he would gladly live all of those days as if they were his last. These words taught me to embrace the difficulties of life, to find happiness in them, and to not see them as the means to an end. This resonated with me throughout my Ph.D. As you may imagine, concluding a Ph.D. in mathematics, especially in a country like Brazil, is not an easy task. The frustrations and uncertainties of this path are tremendous, and so are the effort and the dedication needed to accomplish it. This beautiful idea of finding joy in the challenges of life was the key factor that helped me move forward, from undergrad student to a researcher, a scientist.The author of the quotation was my father, who tragically passed away a couple of months before my defense. To him, I own who I am.My family was the pillar that supported me all those years, and to them, I am profoundly grateful. To my mother Ivoneide Teixeira, who teaches me every day, through example, the importance of dedicating and sacrificing yourself to your work, a value I carry deeply in me. She, like my father, does not come from a privileged background and had to struggle and work hard all her life. Her i ii dedication to work and her unbreakable spirit, she never stops fighting for what she wants, are core values that I try to carry with me. She is the person I respect and own the most. I also thank my sisters, Fernanda Maia and Natália Maia, for the support they always gave me, for being an example to me in several ways, and for the joy you always brought to my life. It is a privilege to have you as my siblings.The last member of my family is my girlfriend, Jessica Dantas. We have been together since high school, so we have grown beside one another. Through the hardships and ups and downs of a relationship, I loved and admired her every step of the way. Her life was, in many ways, much tougher than mine. That never made her shine away from any challenge thrown at her. And after overcoming them, she still finds the will to pursue her future goals, which are ple...