Spijker's lemma

In mathematics, Spijker's lemma is a result in the theory of rational mappings of the Riemann sphere. It states that the image of a circle under a complex rational map with numerator and denominator having degree at most n has length at most 2.

Applications

Spijker's lemma can be used to derive a sharp bound version of Kreiss matrix theorem.

See also

  • Weisstein, Eric W. "Spijker's Lemma". MathWorld.

References

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