FUNCTION: LieTools/SgLaplacian
USAGE: SgLaplacian(gpoly);
SYNOPSIS: SgLaplacian(gpoly) yields the action of the g-invariant 
  Laplacian on a polynomial gpoly in S(g).
CAVEATS: requires a previously initialized global Lie algebra environment.
  (See LieTools[gSetup].)
EXAMPLE: 
> with(LieTools):
> gSetup(G,2):
Setting up Gtype = G   rnk = 2
> gpoly := g[14]^2;

                                         2
                           gpoly := g[14]

> SgLaplacian(gpoly);

                                  0

> c2 := add(add(BI[i,j]*g[i]*g[j],i=1..dimg),j=1..dimg):
> SgLaplacian(c2*gpoly);

                                      2
                              36 g[14]

SEE ALSO: LieTools[SgCasimir], LieTools[Euler]
