Pseudo vector bundles and quasifibrations

We prove a topological result concerning the kernel ker d of a morphism d: E⟶ F of holomorphic vector bundles over a complex analytic space. As a consequence, weshow that the projectivization P(ker d) is a quasifibration up to some dimension. We givean application to the Abel-Jacobi map of a Riemann surface, and to the space of rational curves in the symmetric product of a Riemann surface.