Sōichi Kakeya

Soichi Kakeya (Japanese挂 谷 宗 一, Kakeya Soichi; born January 18, 1886 in Hiroshima Prefecture, † January 9, 1947 ) was a Japanese mathematician, known for the Kakeya problem. Kakeya studied at the Tokyo Imperial University and taught at the Imperial University of Tohoku, and at the Pedagogical University of Tokyo. He was from 1935 professor at the Tokyo Imperial University and from 1944 director of the Statistical Institute.

Kakeya set 1917 the task in the plane to find the minimum area in which a needle of length one can be rotated continuously. 1928 published Besikowitsch evidence that the surface area can be as small .. Besikowitsch had in 1917 a similar problem solved without knowledge of Kakeyas work (published in 1920 in a Russian journal ). The problem has applications in various fields of mathematics of the analysis to combinatorics and number theory and generalizations of the Kakeya problem still partially open, as the Kakeya conjecture: a Besikowitsch quantity ( containing a unit needle in either orientation ) in the n- dimensional Euclidean space has at least Hausdorff dimension n (open for n greater than or equal 3).

Kakeya is also for the set of Kakeya (1912 /13) and Gustav Eneström (1893 ) to include a polynomial of degree n with real coefficients has its zeros in the unit disk in the complex plane.

In 1934 he was inducted into the Japan Academy, whose imperial price he received in 1928.