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2206.10102

EXISTENCE OF THE MANDELBROT SET IN PARAMETER PLANES FOR SOME GENERALIZED MCMULLEN MAPS

Suzanne Boyd, Alexander Mitchell

correcthigh confidence
Category
math.DS
Journal tier
Strong Field
Processed
Sep 28, 2025, 12:56 AM

Audit review

The paper proves the existence and multiplicity of baby Mandelbrot sets in parameter slices of R_{n,a,c}(z)=z^n+a/z^n+c by constructing explicit quadratic-like restrictions of R itself on wedge-shaped domains and invoking a standard parameter-winding criterion (its Theorem 2.3) together with Douady–Hubbard straightening. The candidate solution establishes the same conclusions via a different route: a root-lift semiconjugacy on an n-th root sector, parabolic anchors, and quadratic-like first return maps for a lifted degree-2 map. Parameter ranges and multiplicity statements match the paper’s theorems. Minor presentation gaps (e.g., analyticity of varying boundaries) are not substantive. Hence both are correct, with different proofs.

Referee report (LaTeX)

\textbf{Recommendation:} minor revisions

\textbf{Journal Tier:} strong field

\textbf{Justification:}

The manuscript extends classical baby-Mandelbrot results for McMullen maps to the two-parameter family with translation, using direct quadratic-like restrictions of R and a standard parameter-winding criterion. Arguments are standard, ranges are explicit, and multiplicities match symmetries. Minor clarifications would improve rigor around analyticity of varying boundaries and properness. Overall, the contribution is solid and well-positioned within complex dynamics.