An extended Fatou-Shishikura inequality and wandering branch continua for polynomials

Academic Article


  • Let P be a polynomial of degree d with Julia set JP. Let N~ be the number of non-repelling cycles of P. By the famous Fatou-Shishikura inequality N~≤d-1. The goal of the paper is to improve this bound. The new count includes wandering collections of non-(pre)critical branch continua, i.e., collections of continua or points Qi⊂JP all of whose images are pairwise disjoint, contain no critical points, and contain the limit sets of eval(Qi)≥3 external rays. Also, we relate individual cycles, which are either non-repelling or repelling with no periodic rays landing, to individual critical points that are recurrent in a weak sense.A weak version of the inequality reads Ñ+Nirr + χ + ∑i(eval(Qi)-2) ≤ d - 1 where Nirr counts repelling cycles with no periodic rays landing at points in the cycle, {Qi} form a wandering collection BC of non-(pre)critical branch continua, χ=1 if BC is non-empty, and χ=0 otherwise.
  • Published In

    Digital Object Identifier (doi)

    Author List

  • Blokh A; Childers D; Levin G; Oversteegen L; Schleicher D
  • Start Page

  • 1121
  • End Page

  • 1174
  • Volume

  • 288