dv82matt comments on The dangers of zero and one - Less Wrong

27 Post author: PhilGoetz 21 November 2013 12:21PM

You are viewing a comment permalink. View the original post to see all comments and the full post content.

Comments (68)

You are viewing a single comment's thread.

Comment author: dv82matt 17 November 2013 05:54:50AM *  11 points [-]

But can you be 99.99% confident that 1159 is a prime?

This doesn't affect the thrust of the post but 1159 is not prime. Prime factors are 19 and 61.

Comment author: lalaithion 17 November 2013 05:15:07PM 9 points [-]

That may have, in fact, been the point. I doubt many people bothered to check.

Comment author: PhilGoetz 17 November 2013 07:41:52PM 4 points [-]

Indeed. :)

Comment author: ChrisHallquist 22 November 2013 05:08:21PM -2 points [-]

As soon as I saw that in the post, I began checking it. In my head. Have I mentioned I'm good at math?

Comment author: Fhyve 25 November 2013 08:19:50AM -1 points [-]

That only means you are merely good at arithmetic. Can you prove, say, that there are no perfect squares of the form

3^p + 19(p-1)

where p is prime?

Comment author: bentarm 21 November 2013 12:46:12AM 0 points [-]

I was about 80% sure that 1159 was not prime, based on reading that sentence. It took me <1 minute to confirm this. I can totally be more than 99.99% sure of the primality of any given four-digit number.

In fact, those odds suggest that I'd expect to make one mistake with probability >0.5 if I were to go through a list of all the numbers below 10,000 and classify them as prime or not prime. I think this is ridiculous. I'm quite willing to take a bet at 100 to 1 odds that I can produce an exhaustive list of all the prime numbers below 1,000,000 (which contains no composite numbers), if anyone's willing to stump up at least $10 for the other side of the bet.

Comment author: Gurkenglas 18 December 2013 03:12:24PM *  3 points [-]

You can only simply exponentiate the chance of success if it doesn't correlate over multiple repetitions. I would say that if the list of primes below 10^6 you were referencing has at least one error in the first 10^5, it would be more likely to be faulty later, and vice versa, which means that your gut estimates on the two scales might be noncontradictory.

Comment author: PhilGoetz 21 January 2014 05:52:58PM 0 points [-]

Right. Say you write code to generate primes. If there's no bug, all your answers are correct. If there's a bug in your code, probably lots of your answers are incorrect.