Jacques Martinet passed away on January 10, 2026. He was one of the founding fathers of the Bordeaux school of number theory.
After completing his PhD under the supervision of Claude Chabauty in Grenoble, Jacques Martinet was appointed in 1968 to the University of Bordeaux, together with a small group of young mathematicians tasked with revitalizing the discipline there. He retired in 1999 and remained professor emeritus until 2014. Even very recently, he continued to visit the IMB to attend research seminars and to exchange ideas with members of his group.
Throughout his career, Jacques Martinet explored a wide range of research topics. He initially worked in algebraic number theory on questions related to Galois module structure, then on discriminants of number fields and on algorithmics. His study of ideal class groups led him to the geometry of numbers, after which he devoted himself entirely to Euclidean lattices and the associated sphere packings. He is the author of a book that has become a standard reference in the field.
Deeply passionate about his research, Jacques Martinet pursued his mathematical activities well beyond his retirement—he used to say that he had “returned to the CNRS”—and even after the end of his emeritus status. He leaves behind a remarkably rich website gathering his publications, notes, and numerical tables.
Jacques Martinet was also a highly dedicated teacher, appreciated by many generations of students. In their testimonies, his numerous former students praise his qualities as a PhD supervisor, highlighting his availability and encouragement, as well as the great scientific freedom he granted them. At least 13 of his students went on to pursue academic careers, spreading far beyond Bordeaux.
Over the course of his career, Jacques Martinet held many responsibilities, serving on national university committees and CNRS committees, on local councils, and as head of the Department of Mathematics and Computer Science. In order to foster the development of arithmetic algorithmics, he founded the A2X laboratory in 1993, which he directed until 2000. This branch of number theory has since become a distinctive feature of Bordeaux mathematics and is now supported by INRIA.
After mathematics, music was his second passion, particularly the works of Schubert and Schumann. Jacques loved to sing and often practiced singing with colleagues and friends. One could even hear him humming in the corridors of the laboratory…
Through the originality of his ideas and the quality of his work, Jacques Martinet brought national and international recognition not only to the Number Theory group, but more broadly to mathematics in Bordeaux. His love of teaching, his passion for research, and his dedication to serving the community ensure that he will remain a model and a source of inspiration for all academic teachers and researchers.