Which mathematician defined the Voronoi diagram, Mikhail Kravchuk or Georgy Voronoy?
Mikhail Kravchuk: Mykhailo Pylypovych Kravchuk, also Krawtchouk (Ukrainian: Миха́йло Пили́пович Кравчу́к ) (September 27, 1892 – March 9, 1942), was a Soviet Ukrainian mathematician who, despite his early death, was the author of around 180 articles on mathematics. Georgy Voronoy: Georgy Feodosevich Voronoy (Ukrainian: Георгій Феодосійович Вороний ; Russian: Гео́ргий Феодо́сьевич Вороно́й ; 28 April 1868 – 20 November 1908) was a Russian and Ukrainian mathematician. Georgy Voronoy:  Among other things, he defined the Voronoi diagram.
Georgy Feodosevich Voronoy