% $Date: 2004/10/04 17:25:12 $ $Author: nthiery $ $Revision: 1.1.1.2 $

\begin{Mhelppage}{x2XX}{S. Veigneau}

  \begin{MInfo}
    \eng{from the basis of monomials to XX Schubert basis}
  \end{MInfo}
      
  \begin{MCalls}
    \Mcall{pol}
  \end{MCalls}
%
  \begin{MParameters}
    \param{pol}
    \eng{any expression in the basis of monomials} 
  \end{MParameters}
%
  \begin{MIntro}
    \eng{The {\Mthis} function converts any expression from the basis
      of monomials to XX Schubert basis. It uses a different algorithm
      than \Mex{ToXX} (taking the leading monomials successively).
    
      The result is not expanded.
 
      One may add \Mex{NoExpand} just after the argument \Mex{pol} to
      choose not to expand the expression \Mex{pol} before treating
      it.
    
      One may add \Mex{Collect} just after the argument \Mex{pol} or
      just after the argument \Mex{NoExpand} to collect the result.  }
  \end{MIntro}
%
\begin{MExample}{ex1}
%
\begin{Mexin}
muEC::SP::x2XX((1+q)^5*x1*x2^2, NoExpand);
\end{Mexin}
\begin{Mexout}
       5
(q + 1)  (y3 XX[2, 3, 1] - y1 (y1 XX[2, 1] - y3 XX[1, 3, 2] -

   y2 (y2 XX[1] - XX[2, 1] + XX[1, 3, 2]) + XX[2, 3, 1] +

   XX[3, 1, 2] - XX[1, 4, 2, 3]) +

   y1 (y1 XX[2, 1] + XX[2, 3, 1]) - XX[3, 2, 1] +

   XX[2, 4, 1, 3])
\end{Mexout}
\begin{Mexin}
muEC::SP::x2XX((1+q)^5*x1*x2, Collect);
\end{Mexin}
\begin{Mexout}
     5         4          3          2
(y1 q  + 5 y1 q  + 10 y1 q  + 10 y1 q  + 5 y1 q + y1)

                         5            4             3
   XX[1, 3, 2] + (y1 y2 q  + 5 y1 y2 q  + 10 y1 y2 q  +

             2
   10 y1 y2 q  + 5 y1 y2 q + y1 y2) XX[1] +

     5      4       3       2
   (q  + 5 q  + 10 q  + 10 q  + 5 q + 1) XX[2, 3, 1]
\end{Mexout}
\end{MExample}
%
\MRelatedFunctions{}
\end{Mhelppage}
