Historical clue formulations

• Prove it — 2009-10-11
• Something to prove — 2009-06-05
• Provable proposition — 2004-05-20
• Pythagorean ___ — 2003-03-18
• Something to prove — 2002-08-30
• Math statement — 2001-05-29
• Pythagorean nugget — 1995-09-14