Maximal Residue Difference Sets Modulo p

Duncan A. Buell, Kenneth S. Williams
1978 Proceedings of the American Mathematical Society  
Letp = 1 (mod 4) be a prime. A residue difference set modulo/) a¡ "¡ -a¡ is a set 5 = {a,} of integers a, such that ( -) = +1 and (-) = + 1 for all i and y with / # j, where ( -) is the Legendre symbol modulo p. Let rrij, be the cardinality of a maximal such set S. The authors estimate the size of /Up.
doi:10.2307/2042597 fatcat:apkbeeb6mjcclalab5qugbgjhq