`defpoly'
---------

defpoly(ALG)
     :: Returns the defining polynomial of root ALG.

RETURN
     polynomial

ALG
     algebraic number (`root')

   * Returns the defining polynomial of root ALG.

   * If the argument ALG, a root, is `#N', then the main variable of
     its defining polynomial is `t#N'.

     [1] defpoly(A0);
     t#0^2-2

Reference
     *Note `newalg': newalg, *Note `alg': alg, *Note `algv': algv

