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Message boards : General discussion : Pardon my ignorance

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TheCruelLogician

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Message 122999 - Posted: 29 Nov 2018 | 1:02:30 UTC

In reference to the sieve subprojects, what is a factor? I know this is a pretty elementary question, but my background is in the liberal arts / humanities (BA History / Political Science, Philosophy minor) and the only college level mathematics I took was MAT 101 (Algebra) and STA 101 (Basic Statistics). Obviously I know what factorization is and I know what a prime factor is, I'm just wondering if that is what is being referred to, or if I need a math refresher.
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Rafael
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Message 123003 - Posted: 29 Nov 2018 | 2:21:21 UTC - in response to Message 122999.

In reference to the sieve subprojects, what is a factor? I know this is a pretty elementary question, but my background is in the liberal arts / humanities (BA History / Political Science, Philosophy minor) and the only college level mathematics I took was MAT 101 (Algebra) and STA 101 (Basic Statistics). Obviously I know what factorization is and I know what a prime factor is, I'm just wondering if that is what is being referred to, or if I need a math refresher.

When the sieves find "a factor", it means they found a small number that perfectly divides a big one. So by definition, if the big guy is divisible, it is not a prime, and therefore we don't need to waste time testing for primality, for we already know it is composite. The thing with the sieves is that, up to a point, it's faster (and early on, MUCH faster) to find factors and remove potential candidates rather than test said candidates for primality, so we do that to save time.

TheCruelLogician

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Message 123004 - Posted: 29 Nov 2018 | 2:39:42 UTC - in response to Message 123003.

Ok, thanks.
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JimB
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Message 123011 - Posted: 29 Nov 2018 | 12:12:38 UTC