Crossword Genius

They help with proof in problem mastery (6)

Ross

I believe the answer is:

lemmas

'they help with proof' is the definition.
(lemmas are used in mathematical proofs)

'in problem mastery' is the wordplay.
'in' indicates the answer is hidden within the clue.
'LEMMAS' is hidden in the letters of 'problem mastery'.

(Another definition for lemmas that I've seen is " arguments".)

I've seen this clue in The Guardian.
Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.