FUNCTION: Qsf2x - from quasi-symmetric function to the basis of monomials

CALLING SEQUENCE:

Qsf2x(qsf, var)

NCSF[Qsf2x](qsf, var)

PARAMETERS:

qsf = any quasi-symmetric function

var = a list of variables

SYNOPSIS:

• The Qsf2x functions converts a quasi-symmetric function to the basis of monomials.

• The input is any expression in terms of the basic quasi-symmetric functions.

• The quasi-symmetric function qsf is expanded and the result is not collected.

• One may add 'noexpand' just after the argument var to choose not to expand the quasi-symmetric function qsf before treating it.

• Whenever there is a conflict between the function name Qsf2x and another name used in the same session, use the long form NCSF['Qsf2x'].

EXAMPLES:

> with(NCSF):
> Qsf2x(F[2]&*M[1,1],[x1,x2,x3]);
 
    3        3        3          2                2        2   2     2   2
  x1  x2 + x1  x3 + x2  x3 + 3 x1  x2 x3 + 3 x1 x2  x3 + x1  x2  + x1  x3
 
             2   2             2        3        3        3
         + x2  x3  + 3 x1 x2 x3  + x1 x2  + x1 x3  + x2 x3