  In these notes, we survey the homology of the loop group Omega(K) of a
compact group K, also known as the affine Grassmannian of a complex loop group.
Using the Bott picture of H_*(Omega(K)), the homology algebra or Pontryagin
ring, we obtain two new results: A. Factorization of affine Schubert homology
classes. B. Definition of affine Schubert polynomials representing the affine
Schubert homology classes in all types, in terms similar to ordinary Schubert
polynomials.
