Mathologer

Why was this visual proof missed for 400 years? (Fermat's two square theorem) (2020x1)

: 25, 2020

Today's video is about a new really wonderfully simple and visual proof of Fermat's famous two square theorem: An odd prime can be written as the sum of two integer squares iff it is of the form 4k+1. This proof is a visual incarnation of Zagier's (in)famous one-sentence proof.