  For orbifolds admitting a crepant resolution and satisfying a hard Lefschetz
condition, we formulate a conjectural equivalence between the Gromov-Witten
theories of the orbifold and the resolution. We prove the conjecture for the
equivariant Gromov-Witten theories of the nth symmetric product of the complex
plane and the Hilbert scheme of n points in the plane.
