CoherentSheaf ++ CoherentSheaf -- direct sum of coherent sheaves

Synopsis

• Operator: ++

• Usage:

  F ++ G

• Inputs:
  • F, a coherent sheaf
  • G, a coherent sheaf
• Outputs:
  • a coherent sheaf, the direct sum of F and G

Description

i1 : X = Proj(QQ[x,y,z])

o1 = X

o1 : ProjectiveVariety

i2 : OO_X(3) ++ OO_X(4)

        1          1
o2 = OO  (3) ++ OO  (4)
       X          X

o2 : coherent sheaf on X, free of rank 2

i3 : module oo

               2
o3 = (QQ[x..z])

o3 : QQ[x..z]-module, free, degrees {-3, -4}