2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/68803We study an integration theory in circle equivariant cohomology in order to prove a theorem relating the cohomology ring of a hyperkahler quotient to the cohomology ring of the quotient by a maximal abelian subgroup, analogous to a theorem of Martin for symplectic quotients. We discuss applications of this theorem to quiver varieties, and compute as an example the ordinary and equivariant cohomology rings of a hyperpolygon space.18 pages, 1 figureSymplectic GeometryAlgebraic GeometryDifferential Geometry53D20; 53C26text