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Resultant

Given a Polynomial $p(x)$ of degree $n$ with roots $\alpha_i$, $i=1$, ..., $n$ and a Polynomial $q(x)$ of degree $m$ with roots $\beta_j$, $j=1$, ..., $m$, the resultant is defined by

\begin{displaymath}
R(p,q)=\prod_{i=1}^n \prod_{j=1}^m (\beta_j-\alpha_i).
\end{displaymath}

There exists an Algorithm similar to the Euclidean Algorithm for computing resultants (Pohst and Zassenhaus 1989). The resultant is the Determinant of the corresponding Sylvester Matrix. Given $p$ and $q$, then

\begin{displaymath}
h(x)=R(q(t),p(x-t))
\end{displaymath}

is a Polynomial of degree $mn$, having as its roots all sums of the form $\alpha_i+\beta_j$.

See also Discriminant (Polynomial), Sylvester Matrix


References

Pohst, M. and Zassenhaus, H. Algorithmic Algebraic Number Theory. Cambridge, England: Cambridge University Press, 1989.

Wagon, S. Mathematica in Action. New York: W. H. Freeman, p. 348, 1991.




© 1996-9 Eric W. Weisstein
1999-05-25