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<A NAME=DECOMPOSE>

<TITLE>DECOMPOSE</TITLE></A>
<b><a href=r37_idx.html>INDEX</a></b><p><p>



<B>DECOMPOSE</B> _ _ _  _ _ _  _ _ _  _ _ _ <B>operator</B><P>
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The <em>decompose</em> operator takes a multivariate polynomial as argument, 
and returns an expression and a 
<A HREF=r37_0053.html>list</A> of 

<A HREF=r37_0045.html>equation</A>s from which the 
original polynomial can be found by composition. 
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 <P> <H3> 
syntax: </H3>
<em>decompose</em>(&lt;expression&gt;) or <em>decompose</em> 
 &lt;simple\_expression&gt; 
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examples: </H3>
<P><PRE><TT>
decompose(x^8-88*x^7+2924*x^6-43912*x^5+263431*x^4-
          218900*x^3+65690*x^2-7700*x+234)

 

   2                  2            2
  U  + 35*U + 234, U=V  + 10*V, V=X  - 22*X 


     decompose(u^2+v^2+2u*v+1) 

   2
  W   + 1, W=U + V

</TT></PRE><P>Unlike factorization, this decomposition is not unique. Further 
details can be found in V.S. Alagar, M.Tanh, &lt;Fast Polynomial 
Decomposition&gt;, Proc. EUROCAL 1985, pp 150-153 (Springer) and J. von zur 
Gathen, &lt;Functional&gt; 
&lt;Decomposition of Polynomials: the Tame Case&gt;, J. 
Symbolic Computation (1990) 9, 281-299. 
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