At 00:21 -0500 2009-03-09, Jeff Wolfe wrote:
During the same session, we also discussed the possibility of having rules referencing prime numbers, and whether one is a prime.
I once created a rule that ended up harder than I expected because a student thought that zero was odd.
I have in the past had arguments over the primality of the number one (while playing Zendo), so I now carry around a printout of the following web page: http://primes.utm.edu/notes/faq/one.html My friends were amused when I brought it out. I'm not sure what it means that my geeky friends seem to think I'm too geeky.
I would put the explanation as this: If you are going to do anything with primes other than ask "Is this number a prime?", one "definition" leads to extensive use of the phrase "prime other than one". It's much easier to just go with the other definition from the start.
-- Daniel W. Johnson panoptes@xxxxxxxxxx http://members.iquest.net/~panoptes/ 039 53 36 N / 086 11 55 W