  Consider a Hamiltonian action of a compact Lie group on a symplectic manifold
which has the strong Lefschetz property. We establish an equivariant version of
the Merkulov-Guillemin $d\delta$-lemma and an improved version of the
Kirwan-Ginzburg equivariant formality theorem, which says that every cohomology
class has a \emph{canonical} equivariant extension.
