  We give inductive conditions that characterize the Schubert positions of
subrepresentations of a general quiver representation. Our results generalize
Belkale's criterion for the intersection of Schubert varieties in Grassmannians
and refine Schofield's characterization of the dimension vectors of general
subrepresentations. This implies Horn type inequalities for the moment cone
associated to the linear representation of the group $G=\prod_x
\operatorname{GL}(n_x)$ associated to a quiver and a dimension vector $\mathbf
n=(n_x)$.
