On Products of Random Matrices and certain Hecke Algebras associated   with Groups of $2\times 2$ Matrices
  The determination of the density functions for products of random elements from specified classes of matrices is a basic problem in random matrix theory and is also of interest in theoretical physics. For connected simple Lie groups of $2\times 2$ matrices and conjugacy and spherical classes a complete solution is given here. The problem/solution can be re-stated in terms of the structure of certain Hecke algebras attached to groups of $2\times 2$ matrices. 
Jafar Shaffaf