Nayak–Pal symmetry conjecture for Chebyshev maps

Let p∈C[z]p\in\mathbb{C}[z] be a centered polynomial of degree at least 22, let Z(p)Z(p) denote its set of roots, and let CpC_p be the Chebyshev map Cp(z)=z−p(z)p′(z)−p′′(z)p(z)22p′(z)3C_p(z)=z-\frac{p(z)}{p'(z)}-\frac{p''(z)p(z)^2}{2p'(z)^3}. Define Σp={σ∈Aff⁡(C):σ(Z(p))=Z(p)}\Sigma_p=\{\sigma\in\operatorname{Aff}(\mathbb{C}):\sigma(Z(p))=Z(p)\} and ΣCp={σ∈Aff⁡(C):σ(J(Cp))=J(Cp)}\Sigma_{C_p}=\{\sigma\in\operatorname{Aff}(\mathbb{C}):\sigma(J(C_p))=J(C_p)\}, where J(Cp)J(C_p) is the Julia set of CpC_p. The Nayak–Pal conjecture asserts that Σp=ΣCp\Sigma_p=\Sigma_{C_p} for every such polynomial pp.

References

Progress summary

Refreshed
Claimed progress

A new unrefereed manuscript claims progress on the conjecture for an infinite rotationally symmetric family, while the general conjecture remains open.

Nayak and Pal proposed that a centered polynomial’s symmetries coincide with those of the Julia set of its Chebyshev map. Their August 24, 2022 preprint labels this equality as Conjecture 1 and proves only special cases.

Known results

  • For every centered polynomial, Σp⊆ΣCp\Sigma_p\subseteq\Sigma_{C_p} (Nayak and Pal, 2022).
  • Equality holds for unicritical polynomials and for polynomials with exactly two equally multiple roots (Nayak and Pal, 2022).
  • Equality holds for specified cubic and quartic cases; the corresponding Julia sets are connected and locally connected, with Fatou set given by root basins (Nayak and Pal, 2022).

September 2, 2026 claimed family result

A manuscript claims to prove the conjecture for pn(z)=z(zn−1)p_n(z)=z(z^n-1), while also establishing connectivity and basin properties of the associated Julia sets. This extends the recorded special cases but does not, on the available evidence, settle the general conjecture; the manuscript is unrefereed.

Current status (as of September 2026): The equality Σp=ΣCp\Sigma_p=\Sigma_{C_p} is claimed for the family pn(z)=z(zn−1)p_n(z)=z(z^n-1), but the general conjecture remains open and the new claim is unverified.

Sources

Solutions 0

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