  We study (slope-)stability properties of syzygy bundles on a projective space
P^N given by ideal generators of a homogeneous primary ideal. In particular we
give a combinatorial criterion for a monomial ideal to have a semistable syzygy
bundle. Restriction theorems for semistable bundles yield the same stability
results on the generic complete intersection curve. From this we deduce a
numerical formula for the tight closure of an ideal generated by monomials or
by generic homogeneous elements in a generic two-dimensional complete
intersection ring.
