  Varagnolo and Vasserot conjectured an equivalence between the category O for
CRDAHA's and a subcategory of an affine parabolic category O of type A. We
prove this conjecture. As applications, we prove a conjecture of Rouquier on
the dimension of simple modules of CRDAHA's and a conjecture of Chuang-Miyachi
on the Koszul duality for the category O of CRDAHA's.
