Approximation of integration over finite groups, difference sets and association schemes

Hiroki Kajiura, Makoto Matsumoto, Takayuki Okuda

Let $G$ be a finite group and $f:G\to \mathbb{C}$ be a function. For a non-empty finite subset $Y\subset G$, let $I_Y(f)$ denote the average of $f$ over $Y$. Then, $I_G(f)$ is th…