The speaker says the team found that theorem statements by four Fields Medalists, published in the Annals of Mathematics, were strictly false as written.

“There, there were, there were things that, that hu-- And this was Fields Medals, right? We found, we found four Fields medallists have actually proved theorems in the Annals of Mathematics, and if you actually read the statement of the theorem, then strictly speaking, that theorem is not true, right?”