Mathematicians Crossword-2

1234567891011121314151617181920
Across
  1. 8. Bohemian analyst of the XIX Century
  2. 9. Derived the 230 symmetry space groups
  3. 10. Known for the "unitary trick"
  4. 11. Author of a famous history of geometry
  5. 13. "Invisible" collaborator of Littlewood
  6. 14. Gives name to generating sets in polynomial algebras
  7. 18. Did fundamental work on differential systems
  8. 19. Introduced the term "matrix"
  9. 20. Creator of foliation theory
Down
  1. 1. Author of the Nullstellensatz
  2. 2. Gives name to a one-sided surface
  3. 3. Proved that e is transcendental
  4. 4. Founder of classical function theory
  5. 5. Known for work on Babbage's "analytical engine"
  6. 6. Topologist deceased in 1926
  7. 7. Gave a first (incorrect) proof of the 4 color theorem
  8. 12. Gives name to an important class of subgroups
  9. 15. Known for seminal work on symmetries
  10. 16. Gives name to an important class of ODEs
  11. 17. Defender of intuitionism