Janko Boehm boehm@mathematik.uni-kl.de
Lars Kastner kastner@math.fu-berlin.de
Benjamin Lorenz blorenz@math.uni-frankfurt.de
Hans Schoenemann hannes@mathematik.uni-kl.de
Yue Ren ren@mathematik.uni-kl.de
Overview:
We implement a class divisor on an algebraic variety and methods
for computing with them. Divisors are represented by tuples of ideals
defining the positive and the negative part. In particular, we implement the group
structure on divisors, computing global sections and testing linear
equivalence.
In addition to this we provide a class formaldivisor which implements
integer formal sums of divisors (not necessarily prime). A formal divisor
can be evaluated to a divisor, and a divisor can be decomposed into
a formal sum.
Finally we provide a class pdivisor which implements polyhedral formal sums of
divisors (P-divisors) where the coefficients are assumed to be polyhedra with fixed tail cone.
There is a function to evaluate a P-divisor on a vector in the dual of the tail cone. The
result will be a formal divisor.
References:
For the class divisor we closely follow Macaulay2's tutorial on divisors.
Online Manual
