e/Spijker's lemma

Information
has gloss	eng: 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 2nπ.
lexicalization	eng: Spijker's lemma
instance of	c/Lemmas