FUNCTION: LieTools/SgLeadingTerm
USAGE: SgLeadingTerm(gpoly);
SYNOPSIS: This routine will identify the leading term of a polynomial
  in S[g], using the graded lexicographic order defined in
  SgMonoOrder. It returns a two item list [cf,mono] where cf is the coefficient
  of the leading term and mono is the corresponding monic monomial.
EXAMPLE: 
> with(LieTools):
> gpoly := a[1]*g[1]^3 + 2*g[2]*g[3] + c*g[4];

                                3
              gpoly := a[1] g[1]  + 2 g[2] g[3] + c g[4]

> SgLeadingTerm(gpoly);

                                       3
                            [a[1], g[1] ]

SEE ALSO: LieTools[SgDegree], LieTools[SgMonoOrder]
