  In this paper, we introduce semi-symmetric metric Koszul forms and
semi-symmetric non-metric Koszul forms on singular semi-Riemannian manifolds.
Semi-symmetric metric Koszul forms and semi-symmetric non-metric Koszul forms
and their curvature of semi-regular warped products are expressed in terms of
those of the factor manifolds. We also introduce Koszul forms associated to the
almost product structure on singular almost product semi-Riemannian manifolds.
Koszul forms associated to the almost product structure and their curvature of
semi-regular almost product warped products are expressed in terms of those of
the factor manifolds. Furthermore, we generalize the results in \cite{St2} to
singular multiply warped products.
