Isaac Namioka

Isaac Namioka (April 25, 1928 – September 25, 2019) He died at home in Seattle on September 25, 2019.

Early life and education Namioka was born in Tōno, not far from Namioka in the north of Honshu, Japan. When he was young his parents moved farther south, to Himeji. He attended graduate school at the University of California, Berkeley, earning a doctorate in 1956 under the supervision of John L. Kelley. As a graduate student, Namioka married Chinese-American mathematics student Lensey Namioka, later to become a well-known novelist who used Namioka's Japanese heritage in some of her novels.

With Asplund in 1967, Namioka gave one of the first complete proofs of the Ryll-Nardzewski fixed-point theorem.

Following his 1974 paper "separate continuity and joint continuity", a Namioka space has come to mean a topological space X with the property that whenever Y is a compact space and function f from the Cartesian product of X and Y to Z is separately continuous in X and Y, there must exist a dense Gδ set within X whose Cartesian product with Y is a subset of the set of points of continuity of f. The result of the 1974 paper, a proof of this property for a specific class of topological spaces, has come to be known as Namioka's theorem.

In 1975, Namioka and Phelps established one side of the theorem that a space is an Asplund space if and only if its dual space has the Radon–Nikodým property. The other side was completed in 1978 by Stegall.

Awards and honors A special issue of the Journal of Mathematical Analysis and Applications was dedicated to Namioka to honor his 80th birthday. In 2012, he became one of the inaugural fellows of the American Mathematical Society.

Selected publications Books Partially Ordered Linear Topological Spaces (Memoirs of the American Mathematical Society 14, 1957) Linear Topological Spaces (with John L. Kelley, Van Nostrand, 1963; Graduate Texts in Mathematics 36, Springer-Verlag, 1976)

Research papers . . .