The depth of the Rees algebra of three general binary forms

Abstract

One proves that the Rees algebra of an ideal generated by three general binary forms of same degree $\ge 5$ has depth one. The proof hinges on the behavior of the Ratliff-Rush filtration for low powers of the ideal and on establishing that certain large matrices whose entries are quadratic forms have maximal rank. One also conjectures a shorter result that implies the main theorem of the paper.