2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/79409I study flux groups of compact symplectic manifolds. Under some topological assumptions, I give a new estimate of the rank of flux groups and give a method of construcion of compact symplectic aspherical manifolds.8 pages, no figures, corrected version to appear in Math.Res.Letters 7(2000)Symplectic Geometry53C15text