Ideal of the variety of flexes of plane cubics

Abstract

We prove that the variety of flexes of algebraic curves of degree $3$ in the projective plane is an ideal theoretic complete intersection in the product of a two-dimensional and a nine-dimensional projective spaces.

9 pages. The text after formula (34) of version 1 is changed to fix a calculation inaccuracy in the last line of formula (44) of version 1