halfSumOfRoots(RootSystem) -- the half-sum of positive roots

Synopsis

• Function: halfSumOfRoots

• Usage:

  halfSumOfRoots(R)

• Inputs:
  • R, an instance of the type RootSystem,
• Outputs:
  • an instance of the type Weight, the half-sum of positive roots in R

Description

i1 : halfSumOfRoots(rootSystemE(6))

o1 = | 1 |
     | 1 |
     | 1 |
     | 1 |
     | 1 |
     | 1 |

       6
o1 : ZZ