Skip to main content

Timeline for Non-standard Gauss sums

Current License: CC BY-SA 3.0

14 events
when toggle format what by license comment
Apr 13, 2017 at 12:58 history edited CommunityBot
replaced http://mathoverflow.net/ with https://mathoverflow.net/
May 19, 2015 at 21:47 comment added Liss Ok, thank you! I really appreciate your intuition and all the hints. This is not my field, so I was not sure if this was a feasible question. It was worth trying though :), and learning a small bit of the beautiful mathematics behind those questions..
May 19, 2015 at 21:24 comment added GH from MO @Liss: I am pretty sure your sums are not bounded away from zero, i.e. they can be arbitrary small for large $p$. (I don't have a proof though.)
May 19, 2015 at 21:18 comment added Liss thank you, @GHfromMO, this is also interesting approach to know. I already have found similar bound in the work of Konyagin, S.V. and Lev, V.F. (2000) "On the distribution of exponential sums". Theorem 1 there says that a sum of roots of unity taken over a set of $n$ elements is bounded in absolute value from below by $n^{-(p-3)/4}.$ I can use this result to show that the full sum from the beginning of the question (with the prescribed $\chi(k)$) is bounded by $(\frac{p-3}{4})^{-(p-3)/4}.$ Still, as I wrote in some other comment, I was curious to know if a bound away from zero can be obtained.
May 19, 2015 at 4:04 history edited GH from MO CC BY-SA 3.0
added 38 characters in body
May 19, 2015 at 3:58 history edited GH from MO CC BY-SA 3.0
added "Added 1" and "Added 2"
May 19, 2015 at 3:46 comment added Alexey Ustinov $$\sum_{x=1}^p \biggl(\frac{(x-a)(x-b)}{p}\biggr)=p\delta_p(a-b)-1.$$
May 19, 2015 at 3:41 comment added Lucia Yes indeed! I forgot about my comment!
May 19, 2015 at 3:33 comment added GH from MO @Lucia: I think Elkies proves that the Kloosterman sum is not in the prime ideal $(1-\omega_p)$, which rules out zero. Anyways, I gave a direct argument based on your version of Elkies's proof, please check! (I am too sleepy now.)
May 19, 2015 at 3:25 history edited GH from MO CC BY-SA 3.0
added 41 characters in body
May 19, 2015 at 3:20 history edited GH from MO CC BY-SA 3.0
added 41 characters in body
May 19, 2015 at 3:07 comment added Lucia Isn't Elkies's answer about ruling out the maximal size $2\sqrt{p}$ for Kloosterman sums, rather than zero?
May 19, 2015 at 2:56 history edited GH from MO CC BY-SA 3.0
added 106 characters in body
May 19, 2015 at 2:49 history answered GH from MO CC BY-SA 3.0