Sophie Morier-Genoud of the University of Reims Champagne-Ardenne and Valentin Ovsienko of the Centre National de la Recherche Scientifique, Reims, are awarded the 2025 AMS David P. Robbins Prize for their paper “$q$-deformed rationals and $q$-continued fractions,” published in Forum of Mathematics, Sigma.

“In this groundbreaking work .. it is shown that the new concept has striking connections and applications to a wide range of mathematical areas,” according to the prize citation. “The paper has subsequently inspired a profusion of significant further research developments.”

From the citation

The David P. Robbins Prize is awarded to Sophie Morier-Genoud and Valentin Ovsienko for their paper “$q$-deformed rationals and $q$-continued fractions,” published in Forum of Mathematics, Sigma, in 2020.

The authors provide an entirely novel and natural definition of a $q$-analog of the rational numbers. Although a $q$-analog of the integers has been used extensively since the work of Euler, a satisfactory and meaningful $q$-analog of the rationals had remained elusive until this paper. The definition also leads to a natural $q$-analog of the real numbers and has a wide range of fascinating and far-reaching applications.

A $q$-analog of a mathematical concept is a generalization of the concept which depends on a new parameter $q$ in such a way that the original concept is recovered when $q$ is set to 1, and various interesting or useful properties also arise.

Response of Sophie Morier-Genoud

I am thrilled and honored to receive the 2025 David P. Robbins Prize. This is a fantastic recognition and a great encouragement to keep doing what I like to do. I always had a lot of fun doing mathematics and I feel privileged to do it as a profession. 

I am grateful to everyone who helped me in making this path possible. 

I would like to thank all my collaborators and colleagues in the Math Department at the University of Reims and also everywhere in the world who show interest in the math we are doing and contribute to enrich the theory of $q$-numbers.

Response of Valentin Ovsienko

I am deeply moved to receive this prize, named in honor of David P. Robbins, the creator of mathematical concepts that will forever remain among the most beautiful.

My scientific life has been spent trying to connect different topics in algebra, geometry, and mathematical physics. The $q$-numbers, which is a combinatorial notion, are the result of my journey with my younger and much smarter collaborator Sophie Morier-Genoud, following this route. We tried to better understand connections between cluster algebra, Coxeter friezes, Conway’s ideas, the Jones polynomial... We realized that it is impossible to $q$-deform a singular object, but only an infinite sequence of them! In order to $q$-deform rationals, one needs to count them all. We chose the way of counting determined by continued fractions and the action of the modular group.

Working on this subject has been and remains the happiest part of my scientific life. I was captivated by $q$-rationals and I was completely haunted by $q$-irrationals. This happiness, enhanced by interest of other researchers, in itself is reward enough. 

My collaboration with Sophie produced a variety of results, including two energetic children, Lisa and Anatole; the $q$-numbers are also little kids who need to grow up!

Biographical sketch of Sophie Morier-Genoud

Sophie Morier-Genoud is currently full professor at the University of Reims Champagne-Ardenne in France. She completed her PhD at the University of Lyon (2006) under the supervision of Philippe Caldero. She was T.H. Hildebrandt Assistant Professor at the University of Michigan (2006-2008), postdoctoral fellow of the Fondation Sciences Mathématiques de Paris (2008-2009) and associate professor at Sorbonne Université (2009-2021). Her research work is mainly related to algebraic combinatorics and representation theory. She currently serves as an editor for the column “Gems and Curiosities” of the Mathematical Intelligencer.

Biographical sketch of Valentin Ovsienko

Valentin Ovsienko was born in 1964 in the Soviet Union. He received his PhD in 1989 from Moscow State University under the supervision of Alexandre Kirillov. Ovsienko is currently in Reims, Champagne, as a senior researcher at the French Centre National de la Recherche Scientifique. He worked in projective differential geometry, infinite-dimensional Lie algebras, integrable systems, octonions, and, more recently, in combinatorics. Together with Sophie Morier-Genoud, he is the editor of the column “Gems and Curiosities” of the Mathematical Intelligencer, and he invites everyone to write beautiful articles for it.

About the prize

The David P. Robbins Prize is awarded every three years for a paper with the following characteristics: It reports on novel research in algebra, combinatorics, or discrete mathematics and has a significant experimental component; and it is on a topic which is broadly accessible and provides a simple statement of the problem and clear exposition of the work. Papers published within the six calendar years preceding the year in which the prize is awarded are eligible for consideration.

The 2025 prize will be presented at the 2025 Joint Mathematics Meetings in Seattle.

Learn more about the prize and previous recipients.

Contact: AMS Communications.

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The American Mathematical Society is dedicated to advancing research and connecting the diverse global mathematical community through our publications, meetings and conferences, MathSciNet, professional services, advocacy, and awareness programs.

The Math Community Educational Outreach (Math CEO) program at the University of California, Irvine (UCI) will receive the 2025 AMS Award for an Exemplary Program or Achievement in a Mathematics Department.

Founded in 2014, UCI’s Math CEO is an after-school math enrichment program aimed at increasing the number of talented students in STEM from diverse backgrounds by fostering mathematical exploration, mentor development, and community engagement.

From the citation

The University of California, Irvine (UCI) Math CEO program is recognized for its exceptional contributions to the mathematics community and society at large. Established in 2014 by professors Alessandra Pantano and Li-Sheng Tseng, Math CEO targets students from Title I middle schools, providing them with a high-quality after-school math enrichment program. This program brings middle-school students to the UCI campus to work in small groups with undergraduate mentors, many of whom are also from historically marginalized groups, to engage in challenging mathematical tasks and encourage exploration. 

From September 2019 to June 2024, Math CEO engaged a total of 1,221 youth, with 48.6% identifying as female. The ethnic background of the participants was predominantly Latinx (93.5%), with smaller representations of Asian, white, and multiethnic students. In the same five-year period, Math CEO engaged 553 undergraduate mentors, 62.2% of whom were female. The mentors’ ethnic backgrounds were diverse, with significant representation of Asian (52%) and Latinx (30%) students. The undergraduate mentors, many of whom pursue careers in education, receive training in culturally responsive teaching practices and equity in education, significantly impacting their professional development. In a post-survey, 52.3% of the undergraduate mentors expressed interest in teaching or working in education and 45.9% were likely to pursue professions working with children or families.

Recognizing the central role of families in supporting Latinx youth, Math CEO involves parents through bilingual workshops that enhance community awareness of college pathways and financial opportunities. 

Math CEO has been the foundation for numerous research projects in mathematics education, supported by NSF grants, leading to publications and program growth. The program’s success is evident in its expansion to high schools and other regions in Southern California, including a new branch at California State University, Dominguez Hills. Math CEO continues to make a substantial impact on underserved youth, demonstrating a model of systemic, reproducible change that can be implemented by others.

Response of Alessandra Pantano, UCI Math CEO

I am deeply honored to receive the AMS Award for an Exemplary Program in a Mathematics Department on behalf of the UCI Math CEO team. This wonderful award recognizes the work of many colleagues, graduate students, and undergraduate students in developing and delivering the UCI Math Community Educational Outreach (Math CEO) program. For over a decade, Math CEO has provided creative and culturally responsive math enrichment opportunities for hundreds of underprivileged middle-school students, many of which have since “graduated” to high school or even college. Leading this exceptional and dedicated team of volunteers has been the highest pride of my professional life. A special thanks to my partners-in-crime, Prof. Li-Sheng Tseng, codirector of Math CEO, and former graduate student Andres Forero Cuervo, academic coordinator for Math CEO: We could have never done this without you. I look forward to pushing this activity forward and continuing to dedicate my energy to help kids in our county find the way to express their potential – in math and in life! A big thanks to the colleagues who nominated us and to the AMS for recognizing our efforts.  

History of the program

The UC Irvine Math Community Educational Outreach (Math CEO) program was founded in 2014 by math faculty Alessandra Pantano and Li-Sheng Tseng in collaboration with Santa Ana Unified math teacher Jasmina Matasovic. The founders shared a belief that low standardized test scores in underserved communities do not reflect students’ interest and potential to succeed in STEM. Math CEO runs free, weekly, after-school math enrichment sessions, welcoming all youth regardless of math achievement. Starting with only 25 students from one middle school, the program has grown and engaged nearly two thousand students in all, from multiple school districts in Southern California.

About the award

The annual AMS Award for an Exemplary Program or Achievement in a Mathematics Department was established in 2004 and first given in 2006. This award recognizes a department which has distinguished itself by undertaking an unusual or particularly effective program of value to the mathematics community, internally or in relation to the rest of society. Departments of mathematical sciences in North America that offer at least a bachelor’s degree in mathematical sciences are eligible. The award amount is currently $5,000. The award will be presented at the 2025 Joint Mathematics Meetings in Seattle.

Learn more about the award and previous recipients.

Contact: AMS Communications.

*****

The American Mathematical Society is dedicated to advancing research and connecting the diverse global mathematical community through our publications, meetings and conferences, MathSciNet, professional services, advocacy, and awareness programs.
 

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