Keller-Klein retraction (2019)
Nathan Keller and Ohad Klein posted a preprint claiming to prove the Aaronson-Ambainis conjecture. Scott Aaronson announced it on his blog. Within weeks, Paata Ivanishvili found a flaw in Lemma 5.3, and the authors retracted the paper.
The claimed proof collapsed, and the arXiv abstract carried a withdrawal notice.
The episode became a cautionary tale about announcing unverified proofs of the conjecture.
PSI's proof faces the same scrutiny, and the 2019 retraction is why independent checking matters here.
