FUNCTION: CgRho - half the sum of positive roots

CALLING SEQUENCE:

CgRho(typ, rank)

CG[CgRho](typ, rank)

PARAMETERS:

typ = one of the classical group A, B, C or D

rank = the rank of the group

SYNOPSIS:

• The CgRho function computes half the sum of positive roots.

• The result is a list.

• Whenever there is a conflict between the function name CgRho and another name used in the same session, use the long form CG['CgRho'].

EXAMPLES:

> with(CG):
> CgRho(B, 4);
 
                              [1/2, 3/2, 5/2, 7/2]