FUNCTION: LieTools/AddRts
USAGE: AddRts(i1,i2,...); 
SYNOPSIS: AddRts(i1,i2,...) finds the  index of root that is a 
  sum of roots with indices i1,i2,...
CAVEATS: requires a previously initialized global Lie algebra environment.
  (See LieTools[gSetup].)
EXAMPLE: 
> LieTools[gSetup](G,2):
Setting up Gtype = G   rnk = 2
> x := LieTools[AddRts](2,5);
                              x := 6
> 

 
SEE ALSO: LieTools[AddWgts] 
