Yasutaka Shibata Home Page

The isolated singular points which appear at boundary of the moduli space of cubic fivefolds are classified into exactly six types.
All these six isolated singular points have same minimal exponent 7/3.
This number is the critical value in Park's theory.
In this sense, we call the class of these six isolated singularities "extremal cubic fivefold singulariteis".
The normal forms of these six singularities are represented as follows.