English

Total disconnectedness of Julia sets of random quadratic polynomials

Dynamical Systems 2021-07-01 v1

Abstract

For a sequence of complex parameters {cn}\{c_n\} we consider the compositions of functions fcn(z)=z2+cnf_{c_n} (z) = z^2 + c_n, which is the non-autonomous version of the classical quadratic dynamical system. The definitions of Julia and Fatou sets are naturally generalized to this setting. We answer a question posed by Br\"uck, B\"uger and Reitz, whether the Julia set for such a sequence is almost always totally disconnected, if the values cnc_n are chosen randomly from a large disk. Our proof is easily generalized to answer a lot of other related questions regarding typical connectivity of the random Julia set. In fact we prove the statement for a much larger family of sets than just disks, in particular if one picks cnc_n randomly from the main cardioid of the Mandelbrot set, then the Julia set is still almost always totally disconnected.

Keywords

Cite

@article{arxiv.2004.06955,
  title  = {Total disconnectedness of Julia sets of random quadratic polynomials},
  author = {Krzysztof Lech and Anna Zdunik},
  journal= {arXiv preprint arXiv:2004.06955},
  year   = {2021}
}