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I was doing some reading about the Rieman hypotesis like a month ago - when searching I came across this very same post - not sure if here or somewhere else, bu
by ericol 7y ago
I was doing some reading about the Rieman hypotesis like a month ago - when searching I came across this very same post - not sure if here or somewhere else, but I read that the stric definition of a prime number (It has to be divisible only by itself, and obviously _also_ by 1) rules out 1 bcause it is only divisible by itself. I mean, it is divisible by one, but that doesn't count as _also_.
- glial 7y agoLike everything else in mathematics, the definition of 'prime' which excludes 1 is a convenient convention. If we don't let 1 be a prime number, then by the "Fundamental theorem of arithmetic"[1] we can say that every number is either prime or a unique product of primes. If we let 1 be a prime, we could write e.g. 6=2x3, or 6=2x3x1x1, so the factorization would no longer be a unique product of primes. https://en.wikipedia.org/wiki/Fundamental_theorem_of_arithmetic https://en.wikipedia.org/wiki/Fundamental_theorem_of_arithme...