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

Math.RootLoci.CSM.Equivariant.Umbral

Description

The umbral formula for the open CSM classes.

The formula is the following:

A(mu)    = 1 / aut(mu) * prod_i Theta(mu_i)
Theta(p) = ( (1 + beta*s) (alpha+t)^p - (1 + alpha*s) (beta+t)^p ) / ( alpha - beta )

and the umbral subtitution resulting in the CSM class (at least for length(mu)>=3) is:

t^j  ->  P_j(m)
s^k  ->  (n-3)(n-3-1)(...n-3-k+1) * Q(n-3-k)

Note that Theta(p) is actually a (symmetric) polynomial in alpha and beta; furthermore it's linear in s and degree p in t.

Synopsis

The umbral variables

data ST Source #

A monomial s^k * t^j

Constructors

ST !Int !Int 

Instances

Instances details
Eq ST Source # 
Instance details

Defined in Math.RootLoci.CSM.Equivariant.Umbral

Methods

(==) :: ST -> ST -> Bool #

(/=) :: ST -> ST -> Bool #

Ord ST Source # 
Instance details

Defined in Math.RootLoci.CSM.Equivariant.Umbral

Methods

compare :: ST -> ST -> Ordering #

(<) :: ST -> ST -> Bool #

(<=) :: ST -> ST -> Bool #

(>) :: ST -> ST -> Bool #

(>=) :: ST -> ST -> Bool #

max :: ST -> ST -> ST #

min :: ST -> ST -> ST #

Show ST Source # 
Instance details

Defined in Math.RootLoci.CSM.Equivariant.Umbral

Methods

showsPrec :: Int -> ST -> ShowS #

show :: ST -> String #

showList :: [ST] -> ShowS #

Semigroup ST Source # 
Instance details

Defined in Math.RootLoci.CSM.Equivariant.Umbral

Methods

(<>) :: ST -> ST -> ST #

sconcat :: NonEmpty ST -> ST #

stimes :: Integral b => b -> ST -> ST #

Monoid ST Source # 
Instance details

Defined in Math.RootLoci.CSM.Equivariant.Umbral

Methods

mempty :: ST #

mappend :: ST -> ST -> ST #

mconcat :: [ST] -> ST #

Pretty ST Source # 
Instance details

Defined in Math.RootLoci.CSM.Equivariant.Umbral

prettyMixedST :: forall b c. (Pretty b, Num c, Eq c, IsSigned c, Pretty c) => FreeMod (FreeMod c b) ST -> String Source #

The umbral formula

theta :: ChernBase base => Int -> FreeMod (ZMod base) ST Source #

Theta(p) is defined by the formula

Theta(p) = ( (1 + beta*s) (alpha+t)^p - (1 + alpha*s) (beta+t)^p ) / ( alpha - beta )

This is actually a polynomial in alpha,beta,s,t, also symmetric in alpha and beta

thetaQ :: ChernBase b => Int -> FreeMod (QMod b) ST Source #

Same as theta but with rational coefficients

integralUmbralFormula :: ChernBase base => Partition -> FreeMod (ZMod base) ST Source #

This is just prod_i Theta_{mu_i}

umbralFormula :: ChernBase base => Partition -> FreeMod (QMod base) ST Source #

This is 1/aut(mu) * prod_i Theta_{mu_i}

The affine CSM

affineWeights :: Int -> [ZMod AB] Source #

Weights of the representation Sym^m C^2

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

The top Chern class of the representation is just the product of weights. This represents the zero orbit, and we need to add this to the closure in the affine case!

umbralSubstPolyAff :: ChernBase base => Partition -> ST -> ZMod base Source #

The polynomial to be substituted in the place of s^k*t^j:

s^k*t^j  ->  P_j(m) * Q_k(n-3-k) * (n-3)_k

where n = length(mu) and m = weight(mu).

umbralSubstitutionAff :: ChernBase base => Partition -> FreeMod (ZMod base) ST -> ZMod base Source #

The (affine) umbral substitution

umbralAffOpenCSM :: ChernBase base => Partition -> ZMod base Source #

CSM of the open stratums from the umbral the formula

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

CSM class of the zero orbit (which is just the top Chern class)

umbralAffClosedCSM :: ChernBase base => Partition -> ZMod base Source #

Sum over the strata in the closure (including the zero orbit!)

The projective CSM

umbralSubstPolyProj :: forall base. ChernBase base => Partition -> ST -> ZMod (Gam base) Source #

The polynomial to be substituted in the place of s^k*t^j:

s^k*t^j  ->  P_j(m) * Q_k(n-3-k) * (n-3)_k

where n = length(mu) and m = weight(mu).

umbralSubstitutionProj :: ChernBase base => Partition -> FreeMod (ZMod base) ST -> ZMod (Gam base) Source #

The (projective) umbral substitution

umbralOpenCSM :: ChernBase base => Partition -> ZMod (Gam base) Source #

CSM of the open stratums from the umbral the formula (for length(mu) >= 3)

umbralClosedCSM :: ChernBase base => Partition -> ZMod (Gam base) Source #

Sum over the strata in the closure