
   Syntax       {%IN% &label&} %FACTOR% &expression& {%ON% &pivot&}

   Purpose      Factors &expression& into &label&. The optional &pivot&
                is used to specify the lead term in division.

   Note         &pivot& specifies the lead term in &divisor&.  If you
                want to divide a divisor such as a + b + c into
                a^2*b + b*c + a, then 'a' would be taken automatically
                to be the pivot term if none is specified.  'b' taken
                as the pivot term will give a different result.

   %Example%

   þE1 : c^2 + c*d + b^2
   þIN E1 FACTOR c - d
   E1 : b^2 + 2*d^2+ (c - d)*(c + 2*d)

   PROCEDURE Example(LABEL E ; PARAMETER P) ;
     IN E FACTOR P ;
   EXIT

