application: fulton
uses: group, topaz
Objects
- derived from: AffineNormalToricVariety
UNDOCUMENTED
Properties of CyclicQuotient
- UNDOCUMENTED
- CONTINUED_FRACTION: common::Vector<Integer>
Representation of the number n/q as a Hirzebruch-Jung continued fraction. Take care that this property agrees with the dual property.
- DUAL_CONTINUED_FRACTION: common::Vector<Integer>
Representation of the number n/(n-q) as a Hirzebruch-Jung continued fraction. Take care that this property agrees with the dual property.
- N: common::Integer
Every cyclic quotient variety corresponds to a cone given by the rays (1,0) and (-q,n).
- Q: common::Integer
Every cyclic quotient variety corresponds to a cone given by the rays (1,0) and (-q,n).
- derived from: fan::PolyhedralFan<Rational>
## Toric Variety
Properties of NormalToricVariety
- UNDOCUMENTED
- AFFINE: common::Bool
Evaluates true if the toric variety is affine, i.e. the fan consists of a single cone.
- GENERATING_POLYTOPE: polytope::Polytope<Rational>
Polytope such that the fan of the toric variety is the normal fan of this polytope. This does not necessarily exist. For determining existence and computation we use Shepards theorem.
- PROJECTIVE: common::Bool
Evaluates to true if the corresponding fan is the normal fan of some polytope. Alias for property REGULAR.
- UNDOCUMENTED
- EFFECTIVE_CONE: polytope::Cone<Rational>
The cone of effective divisors in the rational class group A class of divisors D is effective if the corresponding polytope P_D is non-empty
- NEF_CONE: polytope::Cone<Rational>
The cone of nef divisors in the rational class group this is the closure of the cone of ample divisors, where a divisor of the variety is ample if the fan coincides with the normal fan of P_D equivalently, a divisor is nef if the inequalities it defines are tight on P_D
- N_MAXIMAL_TORUS_ORBITS: common::Int
the number of maximal torus orbits. Equals the number of rays of the fan
- SMOOTH: common::Bool
a toric variety is SMOOTH if the fan is PolyhedralFan::SMOOTH Alias for property SMOOTH_FAN.
- UNDOCUMENTED
- DIVISOR: TDivisor
a toric invariant divisor on the variety given by the fan it is represented by n integer vector with entries corresponding to the rays of the fan the actual divisor is stored in the property COEFFICIENTS
- Category: Normal Toric Varieties
The class group Cl(X) of Weil divisors on the toric variety defined by the fan is a finitely generated abelian group of rank N_RAYS-DIM. It usually contains torsion. The rational divisor class group is the tensor product of Cl(X) with Q over Z. This group is torsion free and corresponds to the Picard group if the variety is non-singular.
Properties of RationalDivisorClassGroup
- UNDOCUMENTED
- LIFTING: common::Matrix<Integer, NonSymmetric>
lifts a divisor in the class group onto a divisor on the fan
- PROJECTION: common::Matrix<Integer, NonSymmetric>
maps a divisor on the variety onto its representation in the class group
UNDOCUMENTED
Properties of TDivisor
- UNDOCUMENTED
- CARTIER_DATA: common::Map<Set<Int>, Vector<Rational>>
contains the Cartier data of the divisor, if it is Cartier i.e. contains a list of vertices of the lattice polytope P defined by the divisor and the variety the vertices appear in the same order as the maximal cones of the fan
- COEFFICIENTS: common::Vector<Rational>
The divisor on a toric variety, given as a list of coefficients for the torus invariant divisors corresponding to the RAYS of the fan. Take care of labeling of the Rays.
- SECTION_POLYTOPE: polytope::Polytope<Rational>
The polytope whose lattice points correspond to the global sections of the divisor.
UNDOCUMENTED
Properties of VersalComponent
User Functions
- cf2rational ()
Compute the rational number corresponding to a continued fraction.
- rational2cf ()
Compute the continued fraction corresponding to a rational number.
- UNDOCUMENTED
- hirzebruch_surface ()
takes one parameter r and returns the polyhedral fan corresponding the the Hirzebruch surface H_r
- UNDOCUMENTED
- projective_space ()
takes one parameter r and returns the fan corresponding to the r-dimensional projective space