Testimonios, a new publication from MAA/AMS, brings together first-person narratives from the vibrant, diverse, and complex Latinx and Hispanic mathematical community. Starting with childhood and family, the authors recount their own particular stories, highlighting their upbringing, education, and career paths. Testimonios seeks to inspire the next generation of Latinx and Hispanic mathematicians by featuring the stories of people like them, holding a mirror up to our own community.

The entire collection of 27 testimonios is available for purchase at the AMS Bookstore. MAA members can access a complimentary e-book in their Member Library. AMS members can access a complimentary e-book at the AMS Bookstore. Thanks to the MAA and AMS, we reproduce one chapter per month on Math Values to better understand and celebrate the diversity of our mathematical community with folks who are not MAA members.

Early Life

My grandmother Carmen de Calderón was a school teacher who believed in education as a means to achieve success and who fought for the rights of her daughters to attend college. My parents, both first generation to attend college, met in medical school. They got together when my mother was beginning her residency in pathology and my father had just returned from Prague. I was born two years later under difficult circumstances. Because my father had been labeled a communist and despite being the only neuropathologist in the country, he was unable to find a job; he had been banned from most hospitals. My mother was very ill toward the end of the pregnancy and had a long road to recovery after my birth. My first few years of life were financially challenging for the family. By the time my brother was born, when I was almost four, the situation was a bit more stable.

Grade school. At age four, I started school in the Lycée Français Louis Pasteur in Bogotá. I was very lucky to have been accepted to the only private co-educational, non-religious school my parents could afford. The French government subsidizes these schools in developing countries to ensure that their citizens abroad have access to an education that is comparable to the one they would get in France. Having the opportunity to attend this school opened many doors and played a fundamental role in my deciding to study abroad.

When I think back to my grade school years I think of my best friend who I met in kindergarten 50 years ago. Our friendship started from the shame we experienced to have to wear suspenders. The school uniform required grey wool skirts. These were expensive so to ensure that they lasted a while our mothers had bought a bigger size and put suspenders to hold them in place. This brings me to the second thing I remember about the school—a deep sense of not belonging. The majority of the kids at school were from a very different socioeconomic class, the children and grandchildren of several Colombian presidents attended the school while I was a student there. The third thing that comes to mind are the math classes.

In first grade we learned set theory. We drew Venn diagrams on the playground and used the teacher’s giant blocks (a huge magnification of our own set) to study unions and intersections. We were given a lot of freedom and I could not imagine a better math class. That year we also learned how to count in different bases. With a partner, we used wood structures that resembled buildings, small plastic boxes and beans to count in different bases and to translate between two different bases. It was wonderful.

We learned algebra in sixth grade from a beautiful book that I still remember fondly. At that time the French school system tracked students after ninth grade. I chose the math track. We learned calculus, linear algebra and some basic analysis in tenth, eleventh and twelfth (seconde, première, and terminale).

In 1981, the United States hosted the International Math Olympiad (IMO) for the first time. The U.S. decided to open the competition and invited several countries that had never attended before. Colombia was allowed to bring an eight-person team. The Colombian organizing committee invited a large number of schools in Bogotá to send up to four representatives to participate in the process put in place to form the team. By chance, I ran into the four boys (all in twelfth grade) that had been chosen to represent my school, as they were leaving to go to the first meeting. I asked the school if I could go with them. They told me they were only invited to send four kids, since I was in eleventh grade they did not include me. They told me that I could try to go as an individual, but that the school would not sponsor me. I went to the first session, explained my situation and was allowed to stay, participate in the training and in the qualifying examinations. I made the team. At that stage the school decided to sponsor me!

Although I did terrible in the competition which took place in Washington D.C., participating in the 22nd IMO in 1981 changed my life. I met a number of students who planned to study mathematics after high school; I did not know that was a life option. The French and the French-Canadian kids explained the path they were planning to follow, they were going to go to les écoles preparatoires aux grandes écoles (the preparatory schools for schools like Polytechnique, École Normale Supérieure, etc.) for two years, then take the exams for these schools and go study more mathematics. During those ten days I gathered as much information as possible: what the best preparatory schools were, what the application process looked like, what grades were needed on the baccalauréat, where people lived, etc.

Going to one of those preparatory schools became my main goal. For a Colombian girl in 1981 this was a science fiction scenario, not even a dream. I worked very hard to get the grades I needed in the baccalauréat, filled out the application and found out from the start that these programs heavily favored boys. For example, the schools provided boys with housing in the dormitories and forced girls to find housing elsewhere. Initially, I did not even pay attention to this detail, I was determined to make this work. I was accepted to a couple of places and decided to attend Lycée Louis Le Grand in Paris. Interestingly, the main roadblock I encountered was societal: in Colombia in 1981, young women were supposed to live at home until they got married. It was unheard of for a teenager to move to Paris on her own. My father’s colleagues and siblings told him that no respectable father would ever allow such a thing to happen; it was considered the road to perdition.

Higher Education

Some of the things I recall from the classroom conditions were that tests were returned in descending order of performance and the grades were read out loud. Students were regularly called to the board, loud disparaging comments were common as was the impassive attitude from the math teacher. I recall confronting him, in front of all the class for allowing this abusive environment. The physics teacher was a woman and I recall thinking at the time that it must have been very difficult for her to get where she was. My academic performance, which was deeply correlated to my emotional state, oscillated between very good and terrible. My support system included my aunt who lived in Sicily and who I was able to visit twice, and a dear friend, who I met at the dorm, and her family who basically adopted me. Thanks to their incredible support I managed to finish the academic year. I went back to Colombia for the summer wondering whether I would be able to come back for a second year. The experience had been grueling, my parents financial situation was dire and given my performance during the first year, the school placed me on the track to enter an engineering school. I was not interested in becoming an engineer.

Colombia. I returned to Colombia, took the entrance exam for medicine to the Universidad Nacional de Colombia in Bogotá and passed. As I was supposed to register to enter medical school I realized this was a mistake. It was not possible to transfer to the mathematics program that semester, but physics was an option. So I started my first semester as a physics student in the fall of 1983. This was very fortunate as I was able to immediately enroll in the physics lab that was required for math students in later semesters. In Spring 1984, I transferred to the mathematics program. On May 16, 1984, the Universidad Nacional de Colombia witnessed the bloodiest day in its history. After the kidnapping, torture and murder of a student from the campus in Cali, student assemblies and a demonstration were programmed for that day. Very soon the demonstration turned violent and the army was authorized on campus. As a result, students died and went missing, soldiers and policemen were injured, and the university was taken over by the military, surrounded by barbed wire and closed for over a year.

Those were dark times, I had a sense of having wasted a golden opportunity in France. I was unable to attend college as the National University (a public institution) was closed and we could not afford a private school. During that period I learned how to knit as a way to cope with stress, and I also started to learn English. My mother thought it might come in handy. I did not agree with her. Given the role the U.S. had played in Latin America through the years, I could not imagine why anybody would want to live in the U.S. I only agreed to start because my mother was making such an effort to keep me engaged and preventing me from sinking further into depression. I also decided to learn math on my own.

In the fall of 1984, faculty were allowed back into their offices. I wrote a petition asking that I be allowed to take exams for the courses in the major. I proposed to study on my own (if possible consulting with a faculty member from time to time) and then, when ready, take an exam on the subject. A passing grade in the exam will amount to passing the course. My initial petition was denied, but with time they accepted. The only prerequisite to be able to do this was to have taken the physics lab course I had completed during my first semester. It was a lucky coincidence.

This is how I did most of my undergraduate studies. By the time the university reopened in 1985, I had passed a large number of the required courses to graduate with a degree in mathematics. I took math courses in person for a total of three semesters: one as a physics student, half before the closing and one and a half after the reopening. I had exhausted the offerings by then. A graduation requirement was to have been registered for four semesters. Fortunately, I was missing a history course, which was the only class I took my last semester. I received a BS in math from the Universidad Nacional de Colombia in December 1986.

Three of my professors encouraged me to pursue a PhD in the U.S. I knew I wanted to learn more math, although I had no idea what one did with a PhD in math. I also knew I did not quite fit in Colombia, and that I might do better somewhere else. The English lessons came in handy after all. Furthermore, it was more the hardships and the challenges that I had faced than the mathematics I had learned that prepared me to succeed in graduate school.

Becoming an Immigrant

My advisor was demanding, firm, and straightforward. He deeply valued hard work. These were all characteristics that suited my learning style and spoke to my work ethic. We all have moments of doubt along the way. In the summer of my third year in graduate school, things were not going well. I was unable to focus on research and therefore was getting nowhere with work. In the back of my mind was a nagging question: What was somebody like me doing in a PhD program? My country was falling apart and I was doing nothing to contribute to the community I came from. My life at Stanford felt artificial and meaningless.

One day, toward the end of that summer, Leon asked me to go for a walk. He wanted to understand what was going on. He listened as I explained what I was thinking. He told me that from what he heard about the situation, he could infer that in Colombia I would be an easy target and that he doubted I would be listened to or given a chance to develop any of the ideas I had in mind. Then he told me that if I really wanted to help my country and my community I should become the best mathematician I could be, that that would give me the platform I needed. I am immensely thankful to him for that walk, for what he said and for how he said it. I have wondered many times what would have happened if we had not gone for that walk. Maybe this is a good place to mention that walking plays a huge role in my life. I walk an average of five miles a day. Some of the most important decisions in my life have been made while walking and some of the most important conversations I have ever had have occurred during long walks. I have walked sixty miles in three days for a good cause.

I obtained my PhD in 1992, after the fall of the Berlin wall in November of 1991 and the Tiananmen square protests in June 1989. These two events changed the world and the landscape of the job market for mathematicians in the U.S. I was fortunate to secure jobs that allowed me to continue through the academic path. Many of my classmates were not so lucky.

Through my experiences in Palo Alto and Menlo Park (two very affluent communities neighboring Stanford), as well as through interactions with some of the undergraduate students I taught, I learned that the color of my skin and the way I looked were considered appropriate topics of conversation, as well as reasons to assume I was uneducated and could be taken advantage of. This was a revelation, and something I have reflected upon through the years. I was 23 the first time somebody made it clear that I did not belong in her neighborhood and mocked me under the assumption I did not speak English. I have spent time trying to understand what happens to a person when this abuse starts as a child. I acknowledge that the reality of a Latinx individual born or raised in the U.S. can be very different from mine.

Over the past twenty-five years my research has developed in several distinct, but interconnected directions of analysis: partial differential equations (PDEs), harmonic analysis and geometric measure theory. The most representative theme of my research in PDEs corresponds to the theory that weak notions of regularity are well adapted to the study of boundary behavior of solutions to elliptic PDEs and to free boundary regularity problems. The success of this program, initiated in Chicago with Carlos Kenig, has significantly expanded our knowledge in this field. It has solidified the theory that weak notions of regularity are suitable to study this type of problems, which thus far had only been considered in terms of classical notions of regularity. These ideas have opened a new area in analysis. They were a central theme of the harmonic analysis program at Mathematical Sciences Research Institute (MSRI) in the spring of 2017 and of the research term at Instituto de Ciencias Matemáticas in Spain in the spring of 2018.

I have been recognized with a number of prestigious invitations; I have been a speaker in the analysis session at the International Congress of Mathematicians (ICM 2010) in Hyderabad, India and in the 23rd Nevanlinna Colloquium, ETH, Zurich in 2017. I have given a number of named lectures, among others the NAM Clayton-Woodard Lecture at the Joint Mathematics Meeting in 2016 and the inaugural AMS Mirzakhani lecture at the Joint Mathematics Meeting in 2020. I am a Member of the American Academy of Arts and Sciences (2020), a Miembro Correspondiente de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales (2017) and a Fellow of the AMS (2016). I have been awarded the Blackwell-Tapia Prize (2020) and the Landolt Distinguished Graduate Mentor Award from the University of Washington (2019). Furthermore my research has been continuously supported by the National Science Foundation since 1994.

I have had the good fortune to work with wonderful groups of junior mathematicians: graduate students, postdoctoral fellows and beginning assistant professors. I have made an effort to create vertically integrated groups where team members are both mentors and mentees. Seeing young people grow mathematically and flourish professionally has been very rewarding. They have brought me lots of joy.

I serve the mathematical community in different roles: as co-chair of the Scientific Advisory Committee at Mathematical Sciences Research Institute, as a member of the Board of Trustees of the Institute for Pure and Applied Mathematics (IPAM) at UCLA, as a member of the Board of Directors of the Banff International Research Station in Banff, and was a member of the Board of Directors of the Pacific Institute for the Mathematical Sciences (PIMS) at the University of British Columbia, Vancouver, Canada until early 2020. Currently I am a member of the U.S. National Committees for the International Mathematical Union. I was an elected member of American Mathematical Society (AMS) Editorial Boards Committee (2016–2019) and I currently serve as an elected member of the AMS Nominating Committee.

In winter of 2012, there were several CAMP students in the calculus class I taught. The College Assistant Migrant Program (CAMP) at the University of Washington is federally funded through the U.S. Department of Education’s Office of Migrant Education. It is designed to reach out to and support students from migrant and seasonal farm-worker families during their first year in college. CAMP students are asked to get progress reports from the faculty after each test. The students started coming to my office because they were required to and then kept on coming. One of them talked to me after the final exam about how much it had meant to them to have me, somebody who looked like them, in a room with over 230 students with whom they did not identify. That same student told me that although she was not quite sure what a mentor was or did, she wanted to ask me to be her mentor. I am very happy to share that she is now a third-year medical student at UW, fulfilling her life’s dream.

In 2013, in recognition of the small number of Latinxs in the mathematical sciences and motivated by my experiences with the CAMP students, I brought the idea of a conference for Latinxs in the mathematical sciences to Russ Caflisch, at the time the director of IPAM and to Alejandro Adem, at the time the director of PIMS. Their support and the hard work of my co-organizers brought my idea to fruition in 2015. The first Latinxs in the Mathematical Sciences Conference (LATMATH) was held in April 2015. Over 150 people participated, including undergraduate students, graduate students, postdoctoral scholars and faculty, and researchers in industry and government. Additionally, a group of high school students participated in a math circle and attended a panel featuring UW’s President Ana Mari Cauce, among others. The CAMP student who inspired me to organize the event was also there. The participants expressed enthusiasm for another LATMATH Conference. The second edition took place at IPAM in March 2018 with over 250 participants. Sponsors included National Science Foundation, National Security Agency, Elsevier, the Mathematical Sciences Institutes through the Diversity Initiative, UCLA, Facebook and UW. I am extremely pleased that this conference is now one of the programs in the Diversity Initiative of the Mathematical Sciences Institutes. Latinxs are significantly underrepresented in math and science. There are many problems that contribute to this deficit, and the solution must be multifaceted. This conference is one step in the right direction. The third edition of the conference is scheduled to take place at IPAM in March 2022.

Issues of equity and underrepresentation are at the forefront of my professional interests. I believe that a solid scientific platform allows me to address these issues in settings where they are seldom discussed. To be successful we need to be represented all the way from the bottom to the top of the professional and academic ladders.