Togliatti systems associated to the dihedral group and the weak Lefschetz property

Abstract

In this note, we study Togliatti systems generated by invariants of the dihedral group $D_{2d}$ acting on $k[x_0,x_1,x_2]$. This leads to the first family of non monomial Togliatti systems, which we call $GT-$systems with group $D_{2d}$. We study their associated varieties $S_{D_{2d}}$, called $GT-$surfaces with group $D_{2d}$. We prove that they are arithmetically Cohen-Macaulay surfaces whose homogeneous ideal, $I(S_{D_{2d}})$, is minimally generated by quadrics and we find a minimal free resolution of $I(S_{D_{2d}})$.

To appear in Israel Journal of Mathematics