FUNCTION :  qseries[qfactor] - factor into terms (1-q^i)    
    
CALLING SEQUENCE :  qfactor(f,T)
    
PARAMETERS :   f - qseries or ratpoly
               T   - positive integer (optional)
   
SYNOPSIS :   
                                                              
 qfactor(f,T) attempts to factor f into terms of the form (1-q^i) 
 if possible. T (if present) is the largest i.
EXAMPLES :   
   
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SEE  ALSO :