LieAlgebra _ ZZ -- selects one summand of a semi-simple Lie Algebra

• Operator: _

• Usage:

  g_n

• Inputs:
  • g, an instance of the type LieAlgebra,
  • n, an integer,
• Outputs:
  • h, an instance of the type LieAlgebra,

i1 : g=simpleLieAlgebra("A",2) ++ simpleLieAlgebra("A",2)

o1 = g

o1 : LieAlgebra

i2 : g_0

o2 = 𝔞
      2

o2 : simple LieAlgebra, subalgebra of g

i3 : dynkinDiagram g

o3 = o---o   o---o
     1   2   3   4

i4 : g_0 == subLieAlgebra(g,{1,2})

o4 = true

i5 : g_1 == subLieAlgebra(g,{3,4})

o5 = true