Classic site but I noticed this claim about Euclid's proof of infinitude of primes which is always disputed:<p><a href="https://mathshistory.st-andrews.ac.uk/HistTopics/Prime_numbers/" rel="nofollow">https://mathshistory.st-andrews.ac.uk/HistTopics/Prime_numbe...</a><p>This is one of the first proofs known which uses the method of contradiction to establish a result.<p><a href="https://en.wikipedia.org/wiki/Euclid%27s_theorem" rel="nofollow">https://en.wikipedia.org/wiki/Euclid%27s_theorem</a><p>Euclid is often erroneously reported to have proved this result by contradiction beginning with the assumption that the finite set initially considered contains all prime numbers, though it is actually a proof by cases, a direct proof method.