The Quarterly Journal of Mathematics Advance Access published online on July 11, 2009
The Quarterly Journal of Mathematics, doi:10.1093/qmath/hap023
EXPONENTIAL SUMS WITH CONSECUTIVE MODULAR ROOTS OF AN INTEGER

Department of Computing, Macquarie University, Sydney, NSW 2109, Australia
E-mail: igor{at}ics.mq.edu.au
Received 8 January 2009;
revised 11 June 2009
| Abstract |
|---|
J. Bourgain and the author have recently estimated exponential sums with consecutive modular roots
1/n (mod p), where
is of multiplicative order t
p
modulo a prime p (for some fixed
> 0) and n runs through the integers in the interval [M + 1, M + N] with gcd(n, t) = 1. However, the saving in that bound against the trivial estimate has not been made explicit. It is shown here that for t
p1/2+
one can obtain a fully explicit bound for such exponential sums.