Evgenii Landis

Evgenii Mikhailovich Landis (1921 to 1997) was a Soviet mathematician who worked mainly on partial differential equations, born in Kharkiv in the Ukrainian SSR and died in Moscow. He studied and worked at Moscow State University, where his advisor was Alexander Kronrod and later Ivan Petrovsky. In 1946, together with Kronrod, he rediscovered Sard's lemma, which was unknown in the USSR at the time. He later worked on uniqueness theorems for elliptic and parabolic differential equations, Harnack inequalities and Phragmen-Lindelof type theorems. With Georgy Adelson-Velsky he invented the AVL tree data structure, whose name stands for Adelson-Velsky Landis. His students included Yulij Ilyashenko and Boris Katz.