Projective invariants of quadratic embeddings
In the paper under review we introduce new invariants of projective varieties which are particularly interesting (and always nontrivial) for varieties of small codimension (i.e. those varieties whose codimension does not exceed the dimension). These invariants measure the peculiar behavior of higher secant varieties of the quadratic embedding of our original variety. We study properties of these invariants and their relationship to the known invariants, give a classification of varieties extremal and nearly extremal with respect to these invariants, consider numerous examples, and discuss possible applications.
scientific article; zbMATH DE number 1295408