We prove a general vanishing theorem for the cohomology of products of
symmetric and skew-symmetric powers of an ample vector bundle on a smooth
complex projective variety. Special cases include an extension of classical
theorems of Griffiths and Le Potier to the whole Dolbeault cohomology, and an
answer to a problem raised by Demailly. An application to degeneracy loci is
given.Comment: 12 pages, LaTeX2