What results would follow from or imply "randomness" of the primes? - MathOverflow most recent 30 from http://mathoverflow.net 2013-06-20T10:19:50Z http://mathoverflow.net/feeds/question/65584 http://www.creativecommons.org/licenses/by-nc/2.5/rdf http://mathoverflow.net/questions/65584/what-results-would-follow-from-or-imply-randomness-of-the-primes What results would follow from or imply "randomness" of the primes? Steve Huntsman 2011-05-20T19:51:01Z 2011-05-21T04:43:54Z <p><a href="http://mathoverflow.net/questions/65557/random-versions-of-deterministic-problems" rel="nofollow">This question</a> on random versions of deterministic problems reminded me that many conditional results in number theory hold if the primes are in some sense random, and it is common knowledge that the Riemann hypothesis is tied up in this line of thought. </p> <p>Now, off the top of my head it's not clear what "randomly distributed" really means in the context of the primes. I know that the RH would imply better versions of the prime number theorem, but that's not quite the same. So I am interested in a clarification of this as well as the following</p> <p><strong>Main question:</strong> what results would imply that, and what results would we gain from, the assumption that the primes are "randomly distributed"?</p> http://mathoverflow.net/questions/65584/what-results-would-follow-from-or-imply-randomness-of-the-primes/65593#65593 Answer by Felipe Voloch for What results would follow from or imply "randomness" of the primes? Felipe Voloch 2011-05-20T21:08:24Z 2011-05-21T04:43:54Z <p>The Moebius function $\mu(n)$ is defined for squarefree integers $n$ as $(-1)^k$ if $k$ is the number of prime factors of $n$ (and $\mu(n)$ is defined as $0$ if $n$ is not squarefree). The Riemann hypothesis is equivalent to the statement $\forall \epsilon > 0, \sum_{n &lt; x} \mu(n) = o(x^{1/2 + \epsilon})$. If, on the other hand, you choose $\nu(n) = \pm 1$ randomly for squarefree $n$ and zero otherwise, then by the law of the iterated logarithm, with probability one $\sum_{n &lt; x} \nu(n) = O(\sqrt {x \log \log x})$.</p> <p>Other randomness issues connected with the Riemann hypothesis for L-functions are estimates for sums of the type $\sum e^{2\pi i \alpha n}$ or $\sum \chi(n)$ for a Dirichlet character $\chi$, where $n$ may vary over the integers in an interval or just over primes in an interval (and I should have written $p$ in that case). The mean of these sums is usually easy to figure out and sharp estimates for the deviation from the mean are consequences of (or sometimes equivalent to) the Riemann hypothesis. You can phrase some of these things in terms of primes in arithmetic progressions but then it's not so easy to see the connection with randomness.</p> http://mathoverflow.net/questions/65584/what-results-would-follow-from-or-imply-randomness-of-the-primes/65597#65597 Answer by Timothy Chow for What results would follow from or imply "randomness" of the primes? Timothy Chow 2011-05-20T21:36:27Z 2011-05-20T21:36:27Z <p>Since the primes aren't really random, it's not possible to state precisely the consequences of assuming that the primes are random in the same way that we can state precisely the consequences of the Riemann hypothesis or the axiom of choice. However, using the <a href="http://michaelnielsen.org/polymath1/index.php?title=Cramer%27s_random_model_for_the_primes" rel="nofollow">Cramér random model</a> for the primes, one can "deduce" many conjectures about the primes, such as the Hardy-Littlewood prime tuples conjecture. There is a nice <a href="http://www.utm.edu/~caldwell/preprints/Heuristics.pdf" rel="nofollow">expository article by Chris Caldwell</a> that explains how to use Cramér's model to deduce all kinds of number-theoretical statements.</p> http://mathoverflow.net/questions/65584/what-results-would-follow-from-or-imply-randomness-of-the-primes/65598#65598 Answer by Frank Thorne for What results would follow from or imply "randomness" of the primes? Frank Thorne 2011-05-20T21:36:28Z 2011-05-20T21:36:28Z <p><a href="http://arxiv.org/pdf/math/0606408" rel="nofollow">This</a> is an excellent expository paper by Soundararajan bearing on your question.</p> http://mathoverflow.net/questions/65584/what-results-would-follow-from-or-imply-randomness-of-the-primes/65605#65605 Answer by Simon Lyons for What results would follow from or imply "randomness" of the primes? Simon Lyons 2011-05-20T23:45:05Z 2011-05-20T23:45:05Z <p><a href="http://www.math.uga.edu/~xander/Fa06/Billingsley--Prime_Numbers.pdf" rel="nofollow">Billingsley</a> wrote a nice article on the relationship between numbers, random walks and Brownian motion.</p>