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2201.11055

The Julia sets of Chebyshev’s method with small degrees

Tarakanta Nayak, Soumen Pal

correctmedium confidence
Category
Not specified
Journal tier
Specialist/Solid
Processed
Sep 28, 2025, 12:56 AM

Audit review

The paper’s Theorem 1.1 states deg(Cp) = 3(m + n + r) − 2 − B + s and, when there are no special critical points, deg(Cp) = 3(m + n + r) − 2. Its proof proceeds by counting fixed points: deg(Cp) = m + n + r + deg(Lp), then computes deg(Lp) via factorization and cancellation at the special critical points, yielding deg(Lp) = 2(m + n + r) − 2 − B + s, hence the formula for deg(Cp) . The candidate model derives the same formula by a different route: writing Cp = N/D with D = (p')^3 and N = z(p')^3 − (p')^2 p − (1/2)p^2 p'', then computing deg N = 3d − 2, deg D = 3d − 3 (consistent with the paper’s equation (3)) and explicitly summing cancellations in gcd(N, D) at multiple roots and special critical points to obtain the same degree. Both arguments are logically sound and compatible with the paper’s definitions of special critical points and the fixed-point structure of Cp .

Referee report (LaTeX)

\textbf{Recommendation:} minor revisions

\textbf{Journal Tier:} specialist/solid

\textbf{Justification:}

The manuscript proves a clean, general formula for the degree of Chebyshev’s method and investigates the cubic case dynamics. The methods are standard but carefully implemented; arguments are correct and coherent. The contribution solidly clarifies where and how cancellations reduce degree (via special critical points), which is valuable for complex dynamics of iterative root-finders. Minor expository improvements would enhance clarity.