FUNCTION: LieTools/DecompHg
USAGE: DecompHg(n,Gt); DecompHg(n); DecompHg(n,Gtype,rnk)
SYNOPSIS: DecompHg(n,Gt) returns the decomposition polynomial corresponding to
  the reduction of the space of degree n harmonic polynomials in the symmetric
  algebra of Gt.
  One can also employ DecompHg with a single argument n, but this usage requires 
  a previously initialized global Lie algebra environment. (See LieTools[gSetup].)
EXAMPLE: 
> LieTools[DecompHg](3,G2);

              XX[0, 3] + XX[2, 1] + XX[3, 0] + XX[1, 0] 

SEE ALSO: LieTools[DecompSg]
