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    Symbolic Numerical Solving 
Solving polynomial systems using Gröbner bases and
triangular sets:
    
 
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      Input:  | 
   Zero-dimensional system
   f1 ,...,
      fk  in
      K[x1 ,..., xn]
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      Output:  | 
    Complex roots of 
         f1 = ... = fk = 0
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The algorithm proceeds in 3 steps:
 
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      Step 1:  | 
  
      Compute a reduced lexicographical Gröbner basis of the
      ideal I.
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      Step 2:  | 
  
       Compute a triangular
       system T1 ,...,
       Ts . 
         V(I) is the union
       of the V(Ti ).
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      Step 3:  | 
  
       Use a numerical solver (e.g. Laguerre's method) to find all zeros of
       Ti ,  i=1,..., s .
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