FUNCTION: SfInternal - compute the inner tensor product of symmetric
                       functions 
CALLING SEQUENCE:
-   SfInternal(sf_1, sf_2, b_1, b_2)
-   SYMF[SfInternal](sf_1, sf_2, b_1, b_2)
-  
   
PARAMETERS:
- sf_1, sf_2 =  any symmetric functions
- b_1, b_2   =  any strings denoting names of known bases
 
  
SYNOPSIS:
-  The SfInternal function computes  the  inner tensor product of symmetric
  functions sf_1 and sf_2. This operation  is  also  called  the  internal
  product. Since   sf_1  and  sf_2  may  be  seen  as  virtual  characters,
  SfInternal computes the symmetric function  associated with the  product
  (Kronecker product) of these two virtual characters.
 
 
-  For the basis of products of power-sums,
 
  SfInternal(...p2^j p1^i, ...p2^j' p1^i') =  0            or
                                      =  SfZee([...,2^j,1^i]) ...p2^j p1^i
  whether (...,j,i) <> (...,j',i') or not.
 
 
-  The result is expressed in the p-basis.
 
 
-  In the case  that  sf_1  and  sf_2 are solely expressed in the basis b_1
  and b_2, one may specify these bases.
 
 
-  Whenever  there  is  a conflict between the function name SfInternal and
  another   name   used  in   the   same   session, use   the  long   form
  SYMF['SfInternal'].
 
 
EXAMPLES:
> with(SYMF):
> SfInternal(p3*p3*p2*p1*p1, p3*p3*p2*p1*p1);
 
                                     2      2
                                72 p3  p2 p1
 
> SfZee([3,3,2,1,1]);
 
                                      72
 
> SfInternal(s[3,2,1], p3*h3, 's');
 
                                    2            3
                            - 2/3 p3  - 1/3 p3 p1
 
SEE ALSO: Char2Sf SfPlethysm Sf2Char SfZee