Givental's mirror Landau-Ginzburg model of the quadric hypersurfaces. We deduce the
Picard-Fuchs equation for the narrow periods, which mirror the ambient quantum
cohomology of quadric hypersurfaces. Then by an indirect approach using the irreducibility
of the narrow Picard-Fuchs operator we deduce the Picard-Fuchs equation of the broad
period, which mirrors the quantum cohomology of quadric hypersurfaces involving primitive …