Mean value conjectures for rational maps

Research output: Contribution to journalArticle (Academic Journal)peer-review


Let p be a polynomial in one complex variable. Smale's mean value conjecture estimates |p'(z)| in terms of the gradient of a chord from (z,p(z)) to some stationary point on the graph of p. The conjecture does not immediately generalize to rational maps since its formulation is invariant under the group of affine maps, not the full Mobius group. Here we give two possible generalizations to rational maps, both of which are Mobius invariant. In both cases we prove a version with a weaker constant, in parallel to the situation for Smale's mean value conjecture. Finally, we discuss some candidate extremal rational maps, namely rational maps all of whose critical points are fixed points.
Translated title of the contributionMean value conjectures for rational maps
Original languageEnglish
Pages (from-to)41 - 50
Number of pages10
JournalComplex Variables and Elliptic Equations
Volume51 (1)
Publication statusPublished - Jan 2006

Bibliographical note

Publisher: Taylor & Francis


Dive into the research topics of 'Mean value conjectures for rational maps'. Together they form a unique fingerprint.

Cite this