FUNCTION: LieTools/gcomm
USAGE: gcomm(X,Y);
SYNOPSIS: gcomm(X,Y) computes the commutator of two elements
  X and Y lying in Lie(G)=span{g[1],ldots,g[dimg]}
CAVEATS: requires a previously initialized global Lie algebra environment.
  (See LieTools[gSetup].)
EXAMPLE: 
> LieTools[gSetup](A,2);
Setting up Gtype = A   rnk = 2
> LieTools[gcomm](g[1],g[8]);

                             -g[4] - g[5]

SEE ALSO: 
