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Macaulay2 website
WeylGroups
>
RootSystem
RootSystem -- the class of all root systems
Methods that use an object of class RootSystem :
addRoots(RootSystem,Root,Root)
-- the sum of two roots
cartanMatrix(RootSystem)
-- the Cartan matrix of a root system
dynkinDiagram(RootSystem)
-- the Dynkin diagram of a root system
dynkinType(RootSystem)
-- the Dynkin type of a root system
eval(RootSystem,Weight,Root)
-- evaluate the dual of a root at a Weight
eval(RootSystem,Weight,ZZ)
-- evaluate the dual of a simple root at a Weight
eval(RootSystem,ZZ,Root)
-- evaluate the dual of a root at a fundamental weight
eval(RootSystem,ZZ,ZZ)
-- evaluate the dual of a simple root at another one
halfSumOfRoots(RootSystem)
-- the half-sum of positive roots
isPositiveRoot(RootSystem,Weight)
-- check whether a weight is a positive root
isReduced(RootSystem,BasicList)
-- whether a decomposition in simple reflections is reduced
isRoot(RootSystem,Parabolic,Root)
-- check whether a root is in the sub root system of the parabolic
isRoot(RootSystem,Weight)
-- check whether a weight is a positive root
listWeylGroupElements(RootSystem,ZZ)
-- list all elements of a given length in a Weyl group
longestWeylGroupElement(RootSystem)
-- the longest element of the Weyl group of a root system
longestWeylGroupElement(RootSystem,Parabolic)
-- the longest element of a parabolic subgroup of the Weyl group of a root system
neutralWeylGroupElement(RootSystem)
-- the neutral element of the Weyl group of a root system
norm(RootSystem,Root)
-- the squared norm of a root
numberOfPositiveRoots(RootSystem)
-- the number of positive roots
parabolic(RootSystem,Set)
-- construct a parabolic from a set of simple roots
poincareSeries(RootSystem,Parabolic,RingElement)
-- the generating series of a quotient of the Weyl group by length
poincareSeries(RootSystem,RingElement)
-- the generating series of the Weyl group by length
positiveRoots(RootSystem)
-- the set of all positive roots
positiveRoots(RootSystem,Parabolic)
-- the set of all positive roots in a parabolic sugroups
rank(RootSystem)
-- the rank of a root system
reduce(RootSystem,BasicList)
-- the product of several reflections with respect to simple roots
reflect(RootSystem,BasicList,Root)
-- apply to a root several reflections with respect to simple roots
reflect(RootSystem,BasicList,Weight)
-- apply to a weight several reflections with respect to roots
reflect(RootSystem,ZZ,Root)
-- apply to a root the reflection with respect to a simple root
reflect(RootSystem,ZZ,Weight)
-- apply to a weight the reflection with respect to a root
reflection(RootSystem,Root)
-- the reflection with respect to a root
rootCoefficients(RootSystem,Root)
-- the coefficients at the simple roots
rootCoefficients(RootSystem,Weight)
-- the coefficients at the simple roots
RootSystem ++ RootSystem
-- the direct sum of root systems
RootSystem == RootSystem
-- equality of root systems
rootSystem(RootSystem,Parabolic)
-- the root system of the Levy subgroup of a parabolic
scalarProduct(RootSystem,Weight,Weight)
-- the scalar product of two weights
scalarProduct(RootSystem,ZZ,Weight)
-- the scalar product of a fundamental weight and a weight
scalarProduct(RootSystem,ZZ,ZZ)
-- the scalar product of two fundamental weights
simpleRoot(RootSystem,ZZ)
-- the n-th simple root
weight(RootSystem,BasicList)
-- construct a weight from a list
weight(RootSystem,Vector)
-- construct a weight from a vector
Fixed objects of class
RootSystem
:
rootSystemF4
-- the root system of type F4
rootSystemG2
-- the root system of type G2
For the programmer
The object
RootSystem
is
a
type
, with ancestor classes
MutableHashTable
<
HashTable
<
Thing
.
Menu
rootSystem
-- obtain a root system
cartanMatrix
-- the Cartan matrix of a root system
rank(RootSystem)
-- the rank of a root system
rootSystem(DynkinType)
-- the root system of a given type
rootSystemA
-- a root system of type A
rootSystemB
-- a root system of type B
rootSystemC
-- a root system of type C
rootSystemD
-- a root system of type D
rootSystemE
-- a root system of type E
rootSystem(RootSystem,Parabolic)
-- the root system of the Levy subgroup of a parabolic
rootSystem(DynkinDiagram)
-- the root system corresponding to a Dynkin diagram