4 ms·
1 is considered prime by some.
by willis936 6y ago
1 is considered prime by some.
- WJW 6y agoThere are also people who consider the world to be flat though. There is a very thorough mathematical definition of prime numbers and 1 is not prime according to that definition.
- willis936 6y agoThe definition a prime number is having two factors. As the multiplicative identity, one only has one factor. Some might see primes as being numbers with >=2 factors. This interpretation is less useful. What is completely useless is a definition that makes exclusions of specific numbers as dogma. What does that say about anything? It’s totally arbitrary and unexplanatory.
- spekcular 6y agoNo, that is not the correct definition of a prime. You can find the right one on Wikipedia. The reason that 1 is not a prime is to preserve unique factorization. A basic fact from number theory is that every integer uniquely factors as a product of primes, say 21 = 7 times 3. If 1 were a prime, we'd also have 21 = 7 times 3 times 1. That's bad. In more general number rings, other units (e.g. i) are also not considered primes for the same reason. The exclusion is not arbitrary.
- SuchAnonMuchWow 6y agoAs a complement of your comment: For more information, see Unique Factorization Domains (https://en.wikipedia.org/wiki/Unique_factorization_domain https://en.wikipedia.org/wiki/Unique_factorization_domain) for the generalization of how prime factorization work on things other than integers.
- batpangolin 6y agoFor a mathematician the suggestion that 1 might be a prime is on a par with a suggestion that a circle is technically a type of triangle.
- deleted 6y ago[deleted]
- totalZero 6y agoWhether or not that is true, the code snippet in the article shows this comment: #0 and 1 are not primes
- dan1234 6y agoThat's in the multiprocessing version, which was written by someone else and returns 1229 primes. The original code includes 1 as a prime.