\( \frac{1}{|G|}\sum_{g \in G} \rho(g)\circ \psi_g \)
I think one should not write this with a composition, should one? \( \psi_g \) is a vector space element and a composition connects maps. I prefer anyway to use another symbol (v or w).
Beni (talk) 11:08, 23 June 2015 (CEST)