2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/68740Consider 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 $dδ$-lemma and an improved version of the Kirwan-Ginzburg equivariant formality theorem, which says that every cohomology class has a \emph{canonical} equivariant extension.10 pagesSymplectic Geometry53D20, 58A12text