igusa

Igusa is a Japanese surname most commonly associated with the mid‑twentieth‑century mathematician Jun‑ichi Igusa (1924–2013). Born in Tokyo, Igusa earned his doctorate at the University of Kyoto before joining the faculty at the University of Michigan, where he spent most of his academic career. His research centered on algebraic geometry, number theory, and the theory of automorphic forms. He is renowned for introducing the Igusa zeta function, a p‑adic analogue of the classical zeta function that encodes information about the distribution of solutions to polynomial equations over finite fields. The Igusa zeta function has become a standard tool in arithmetic geometry and singularity theory.

In addition to the zeta function, Igusa developed the theory of Igusa invariants, which classify principally polarized abelian surfaces and play a role in the study of moduli spaces of curves. His work on theta functions and Siegel modular forms earned him the Steele Prize for Mathematical Exposition from the American Mathematical Society in 2001. Igusa authored several influential monographs, notably “Lectures on Modular Forms of One Variable” and “Arithmetic Geometry”.

Beyond the mathematician, the name Igusa appears in several contexts, including the Igusa subvarieties of Shimura varieties and the Igusa curve, a modular curve of characteristic p. The surname remains relatively uncommon, but it is recognized internationally in mathematical literature because of Jun‑ichi Igusa’s lasting contributions to the field.