< SpecialGushelMukaiFourfold -- try to deform to a fourfold of Gushel type

Synopsis

Operator: <
Usage:

< X
Inputs:
- X, a special Gushel-Mukai fourfold, a fourfold of ordinary type
Outputs:
- a special Gushel-Mukai fourfold, a fourfold of Gushel type, a deformation of X

Description

i1 : time X = specialGushelMukaiFourfold "quintic del Pezzo surface";
     -- used 3.78927 seconds

o1 : SpecialGushelMukaiFourfold (Gushel-Mukai fourfold containing a surface of degree 5 and sectional genus 1)

i2 : ? ideal singularLocus grassmannianHull X

o2 = empty subscheme of PP^8

i3 : time X' = < X;
     -- used 8.77866 seconds

o3 : SpecialGushelMukaiFourfold (Gushel-Mukai fourfold containing a surface of degree 5 and sectional genus 1)

i4 : time ? radical saturate ideal singularLocus grassmannianHull X'
     -- used 0.851658 seconds

o4 = one-point scheme in PP^8