  We prove the crepant resolution conjecture for Donaldson-Thomas invariants of
hard Lefschetz CY3 orbifolds, formulated by Bryan-Cadman-Young, interpreting
the statement as an equality of rational functions. In order to do so, we show
that the generating series of stable pair invariants on any CY3 orbifold is the
expansion of a rational function. As a corollary, we deduce a symmetry of this
function induced by the derived dualising functor. Our methods also yield a
proof of the orbifold DT/PT correspondence for multi-regular curve classes on
hard Lefschetz CY3 orbifolds.
