2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/147608We define a homomorphism from (a certain extension of) the fundamental group of the Hamiltonian automorphism group of a symplectic manifold to the group of invertibles in its quantum cohomology ring. The manifold must satify a technical condition similar to weak monotonicity. This revised version has been entirely rewritten. It is more general and contains new examples and applications.44 pages, LaTeX2e, uses the XY-Pic macros for diagramsDifferential Geometrytext