Let 
be group of group order 
and 
be a set of 
elements of 
. If the set of differences 
contains every nonzero element
of 
exactly 
times, then 
is a 
-difference
set in 
of order 
.
Difference Set Order
Explore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "Difference Set Order." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/DifferenceSetOrder.html