His research on the theory of real algebraic varieties, Riemannian geometry, parabolic and elliptic equations was, however, extremely deep and significant in the development of all these topics.
Ang kanyang mga pananaliksik sa teorya ng real algebraic varieties, Riemannian geometry, paparabola at tambilugin equation ay, subalit, lubhang malalim at makabuluhang sa pag-unlad ng lahat ng mga paksang ito.