0
votes
0answers
18 views

Fourier Analysis and applications to Abels groups

Find all functions $f:A\rightarrow C$ such that: $$\sum_{x\in A}|(f*f)(x)|^2 = |A|(\sum_{x\in A}|f(x)|^2)^2$$
3
votes
3answers
172 views

Orthogonality relations of Characters

Could somebody please help me understand the jump from Proposition 10 to Proposition 11 in the following http://www.ms.uky.edu/~pkoester/research/charactersums.pdf Note: The orthogonality relations ...
4
votes
1answer
143 views

Product of Sidon sets

Let $G$ be a compact abelian group with dual $\Gamma$. Let $\Lambda \subset \Gamma$ a Sidon set (see the book of Rudin: Fourier Analysis on Groups for the definition). Consider the set ...