  The ideal of a Segre variety is generated by the 2-minors of a generic
hypermatrix of indeterminates. We extend this result to the case of
Segre-Veronese varieties. The main tool is the concept of weak generic
hypermatrix which allows us to treat also the case of projection of Veronese
surfaces from a set of generic points and of Veronese varieties from a
Cohen-Macaulay subvariety of codimension 2.
