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Macaulay2Doc :: SumOfTwists

SumOfTwists -- the class of all sums of twists

Description

This class is used internally as an abstract representation of a graded module as an infinite direct sum of twists of a coherent sheaf.
i1 : R = QQ[x,y,z]

o1 = R

o1 : PolynomialRing
i2 : X = Proj R

o2 = X

o2 : ProjectiveVariety
i3 : OO_X(*)

        1
o3 = OO  (*)
       X

o3 : SumOfTwists
i4 : peek oo

                    1
o4 = SumOfTwists{OO  , LowerBound{-infinity}}
                   X
i5 : OO_X(>=2)

        1
o5 = OO  (>=2)
       X

o5 : SumOfTwists
i6 : peek oo

                    1
o6 = SumOfTwists{OO  , LowerBound{2}}
                   X
i7 : Ext^0(OO_X^1, OO_X^1)

       1
o7 = QQ

o7 : QQ-module, free
i8 : Ext^0(OO_X^1, OO_X^1(*))

      1
o8 = R

o8 : R-module, free

Functions and methods returning an object of class SumOfTwists :

Methods that use an object of class SumOfTwists :

For the programmer

The object SumOfTwists is a type, with ancestor classes BasicList < Thing.