Comment by RainyDayTmrw
3 days ago
What are some believable but wrong proofs of FLT? Wikipedia also claims that there were historically a lot of them[1], but doesn't provide examples.
[1]: https://en.wikipedia.org/wiki/Fermat%27s_Last_Theorem#Prizes...
Among well-known mathematicians, Gabriel Lamé claimed a proof in 1847 that was assuming unique factorization in cyclotomic fields.
This was not obvious at the time, and in fact, Ernst Kummer had discovered the assumption to be false some years before (unbeknownst to Lamé) and laid down foundations of algebraic number theory to investigate the issue.