Historical clue formulations

• Helpful theorem, in math — 2025-10-13
• Step in a mathematical proof — 2023-01-19
• Helpful theorem, in math — 2022-07-26
• Mathematical proposition — 2021-02-21
• Little theorem within a bigger theorem — 2020-03-21
• Helpful theorem, in math — 2016-07-04
• Subsidiary proposition — 2015-10-11
• Proof part, sometimes — 2004-12-29
• Helping theorem — 2003-05-30
• Auxiliary proposition, in math — 2000-02-21
• Auxiliary proposition — 1998-06-16
• Headword — 1996-08-30
• Headword — 1995-04-08