1-Semiquasihomogeneous Singularities of Hypersurfaces in Characteristic 2

Abstract

In arbitrary characteristic different from 2, the singularities with semiquasihomogeneous equations characterized by the condition to have Saito-invariant 1 are the "classical" quasihomogeneous ones, known over the field of complex numbers as simple elliptic singularities (introduced by K. Saito). Here we find them in characteristic 2 as well: In odd dimensions and for weights E_6~ and E_7~ non-quasihomogeneous equations appear.