On the coefficients of triple product $L$-functions

Abstract

In this paper, we investigate the average behavior of coefficients of the triple product $L$-function $L(f \otimes f \otimes f,s)$ attached to a primitive holomorphic cusp form $f(z)$ of weight~$k$ for the full modular group $SL(2, \Z )$. Here we call $f(z)$ a primitive cusp form if it is an eigenfunction of all Hecke operators simultaneously.