Let $$ A=\{1,2,\ldots,p-1\},\qquad B=\{1,2,\ldots,q-1\} $$ where $p,q$ are primes not necessarily distinct. Is there any elementary way to find the cardinal of the following set $$ AB=\{ab:\ a\in A,\ b\in B\} $$ and also the distribution of them. Thanks!
Asked
Active
Viewed 102 times
3
-
3This seems related to the question http://mathoverflow.net/questions/31663/distinct-numbers-in-multiplication-table – Johan Wästlund Oct 04 '15 at 07:50