On the structure of spaces of commuting elements in compact Lie groups
  In this note we study topological invariants of the spaces of homomorphisms Hom(\pi,G), where \pi\ is a finitely generated abelian group and G is a compact Lie group arising as an arbitrary finite product of the classical groups SU(r), U(q) and Sp(k). 
Alejandro Adem and Jos\'e Manuel G\'omez
math.AT