Name that mathematician

Well, inspired by one of the questions below (number 8), I decided to produce 20 other really bad word plays on the names of famous mathematicians. Some are dead, some are known at Mathcamp (personally). See if you can figure out who they are:
  1. What you shouldn't put before the horse.
  2. Smack those singers with cream & crust.
  3. He's one away from being nothing.
  4. Wealthy rancher
  5. Criminal's modus operandi
  6. What a de-louser looks for.
  7. Lubricator.
  8. Antisocial guy with a transcendental number.
  9. Relatives croak like frogs.
  10. Not able to row.
  11. Bridge over imaginary Greek and Roman foes.
  12. He'll plead to determine your size.
  13. Split him, and you'll hear sheep and a request to enter.
  14. Many bands spend their time doing this.
  15. Proof that those Scandinavians sure know how to tat.
  16. The stack of paper is ready to go.
  17. The bottom of the flower paid for its rule.
  18. You ruin my cold!
  19. What Gallup likes to do.
  20. What mah momma done.
  21. What I do on my winter vacations in La Brea.
Wanna see the answers?
Mathcamp!
Mary Pat Campbell, last updated 4 Sept 2000