# Representations and support.

I am interested in the question: Does there are exist concept of support in representation theory?

When I say support I mean number of non-zero values of $f \in C[G]$. Do you know theorems which talks about the action of elements of $C[G]$ with small support in different representations?

The only example I know about is uncertainty principle which says that for abelian group $supp(f)supp(\hat{f})\geq |A|$.

-
I think the question would benefit from being slightly more precise. It seems better to me if one asks for "theorems that show something like X happens" rather than "theorems which use the concept X". –  Yemon Choi Feb 28 '11 at 7:20