rootSystem(RootSystem,Parabolic) -- the root system of the Levy subgroup of a parabolic

Synopsis

• Function: rootSystem

• Usage:

  rootSystem(R,P)

• Inputs:
  • R, an instance of the type RootSystem
  • P, an instance of the type Parabolic
• Outputs:
  • an instance of the type RootSystem, the root system of the Levy subgroup of P

Description

i1 : R1=rootSystemD(4)

o1 = RootSystem{...8...}

o1 : RootSystem

i2 : P=parabolic(R1,set{1,3,4})

o2 = set {1, 3, 4}

o2 : Parabolic

i3 : R2=rootSystem(R1,P)

o3 = RootSystem{...8...}

o3 : RootSystem

i4 : dynkinType(R2)

o4 = DynkinType{{A, 1}, {A, 1}, {A, 1}}

o4 : DynkinType