coincident-root-loci-0.3: Equivariant CSM classes of coincident root loci
Safe HaskellNone
LanguageHaskell2010

Math.RootLoci.Segre.Equivariant

Description

The equivariant Segre-Schwartz-MacPherson classes

We can recover the Segre-SM classes by dividing the CSM class by the total Chern class of the tangent bundle of the (smooth) ambient variety.

The Segre-SM class is useful because it behaves well wrt. pullback.

Synopsis

The total Chern class

affTotalChernClass :: ChernBase base => Int -> ZMod base Source #

Total Chern class of the representation Sym^m C^2

c(Sym^m C^2) = \prod_{i=0}^m (1 + i*a + (m-i)*b)

affTotalChernClassByDegree :: ChernBase base => Int -> [ZMod base] Source #

Parts of the total Chern class, separated by degree

Inverse of the total Chern class

recipTotalChernClass :: forall base. ChernBase base => Int -> [ZMod base] Source #

Infinite power series expansion (by degree) of the multiplicative inverse of the total Chern class of the representation Sym^m C^2

This is just the sum of all complete symmetric polynomials of the sums.

recipTotalChernClass2 :: forall base. ChernBase base => Int -> [ZMod base] Source #

Another implementation of recipTotalChernClass

recipTotalChernClassSlow :: forall base. ChernBase base => Int -> [ZMod base] Source #

A third, very slow implementation of recipTotalChernClass

divideByTotalChernClass :: ChernBase base => Int -> ZMod base -> [ZMod base] Source #

Divides a polynomial with the total chern class. As the result is an infinite power series, we return it's homogeneous parts as an infinite list.

Equivalent (but should be faster than) to:

separeteGradedParts what `mulSeries` (recipTotalChernClass m)

divideByTotalChernClassSlow :: ChernBase base => Int -> ZMod base -> [ZMod base] Source #

Another, very slow implementation of divideByTotalChernClass

Affine Segre-SM classes

affineOpenSegreSM :: ChernBase base => Partition -> [ZMod base] Source #

Affine equivariant Segre-SM class of the open strata

affineZeroSegreSM :: ChernBase base => Int -> [ZMod base] Source #

Affine equivariant Segre-SM class of the zero orbit

affineClosedSegreSM :: ChernBase base => Partition -> [ZMod base] Source #

Affine equivariant Segre-SM class of the closure of the strata (including the zero orbit!)