CoherentSheaf (*) -- sum of twists

• Operator: (*)

• Usage:

  F(*)

• Inputs:
  • F, a coherent sheaf, or a a sheaf of rings
• Outputs:
  • a sum of twists, a symbolic representation of the graded object consisting of the twists F(n), for all integers n

i1 : R = QQ[x,y,z];

i2 : X = Proj R

o2 = X

o2 : ProjectiveVariety

i3 : Ext^0(OO_X^1, OO_X^1)

       1
o3 = QQ

o3 : QQ-module, free

i4 : Ext^0(OO_X^1, OO_X^1(*))

      1
o4 = R

o4 : R-module, free

i5 : Ext^0(OO_X^1, OO_X(*))

      1
o5 = R

o5 : R-module, free