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Divisor :: moduleToDivisor

moduleToDivisor -- Compute a divisor associated to a module in a ring

Synopsis

Description

Given a rank 1 reflexive module M, this finds a divisor D such that O(D) is isomorphic to M. If IsGraded is true (it is false by default) this assumes we are working on the Proj of the ambient ring.
i1 : R = QQ[x,y,z]/ideal(x^2-y*z)

o1 = R

o1 : QuotientRing
i2 : M = (ideal(y*x,y*z))*R^1

o2 = image | xy yz |

                             1
o2 : R-module, submodule of R
i3 : moduleToDivisor(M)

o3 = -1*Div(z, x) of R

o3 : WDiv
i4 : moduleToDivisor(M, IsGraded=>true)

o4 = -2*Div(z, x) + -1*Div(y, x) of R

o4 : WDiv

See also

Ways to use moduleToDivisor :