Addressing researchers and graduate students in the active meeting
ground of analysis, geometry, and dynamics, this book presents a study
of renormalization of quadratic polynomials and a rapid introduction to
techniques in complex dynamics. Its central concern is the structure of
an infinitely renormalizable quadratic polynomial f(z) = z2 + c. As
discovered by Feigenbaum, such a mapping exhibits a repetition of form
at infinitely many scales. Drawing on universal estimates in hyperbolic
geometry, this work gives an analysis of the limiting forms that can
occur and develops a rigidity criterion for the polynomial f. This
criterion supports general conjectures about the behavior of rational
maps and the structure of the Mandelbrot set.
The course of the main argument entails many facets of modern complex
dynamics. Included are foundational results in geometric function
theory, quasiconformal mappings, and hyperbolic geometry. Most of the
tools are discussed in the setting of general polynomials and rational
maps.