FUNCTION: LieTools/ExtremeChar
USAGE: ExtremeChar(dc,Gt); ExtremeChar(dc); ExtremeChar(dc,Gtype,rnk);
SYNOPSIS: ExtremeChar(dc,Gt) finds a dominant weight appearing in a dominant 
  character that can not be a weight occuring in the finite dimensional
  representations corresponding to the other dominant weights in dc.
  ExtremeChar can be called with a single argument, dc, if a global Lie 
  algebra environment has been previously initialized (see LieTools[gSetup]).
EXAMPLE: 
> dc := LieTools[DomChar]([2,2],A2);

      dc := X[2, 2] + X[0, 3] + X[3, 0] + 2 X[1, 1] + 3 X[0, 0]

> xc := LieTools[ExtremeChar](dc,A2);

                            xc := X[2, 2]

SEE ALSO: LieTools[Char], LieTools[DomChar], LieTools[DecomposeChar]
