Consider the Hamiltonian action of a compact connected Lie group on a transversely
symplectic foliation which satisfies the transverse hard Lefschetz property. We
establish an equivariant formality theorem and an equivariant symplectic
-lemma
in this setting. As an application, we show that if the foliation is also Riemannian,
then there exists a natural formal Frobenius manifold structure on the equivariant
basic cohomology of the foliation.