Peer-reviewedCC BY 4.0Axioms
Sharp Bounds for Schippers–Schwarzian Derivatives via the Schur-Parameter Method
- 1School of Big Data and Artificial Intelligence, Chizhou University, Chizhou 247000, China
- 2School of Mathematics and Systems Science, Liaocheng University, Liaocheng 252000, China
Abstract
In the present paper, we derive sharp bounds for Schippers–Schwarzian derivatives of functions belonging to the two core Ma–Minda subclasses associated with the canonical half-plane majorant ψ(z)=1+z1−z: the convex class C(ψ) and starlike class S*(ψ), and the generalized Robertson class SPα(β). All derivations avoid Carathéodory coefficients cn; we only express the Taylor coefficients of Schwarz functions via Schur polynomials Fk(γ1,…,γk), then reduce each functional to a single-variable optimization, and construct explicit extremal Schwarz kernels as well as integral-form extremal univalent mappings.
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BibTeX
@article{wang2026sharp,
title = {{Sharp Bounds for Schippers–Schwarzian Derivatives via the Schur-Parameter Method}},
author = {Hong Wang and Xiaoyuan Wang},
journal = {Axioms},
year = {2026},
month = oct,
doi = {10.3390/axioms15100783},
url = {https://www.mdpi.com/2075-1680/15/10/783},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Sharp Bounds for Schippers–Schwarzian Derivatives via the Schur-Parameter Method
AU - Hong Wang
AU - Xiaoyuan Wang
PY - 2026
DA - 2026/10/19
JO - Axioms
DO - 10.3390/axioms15100783
UR - https://www.mdpi.com/2075-1680/15/10/783
AB - In the present paper, we derive sharp bounds for Schippers–Schwarzian derivatives of functions belonging to the two core Ma–Minda subclasses associated with the canonical half-plane majorant ψ(z)=1+z1−z: the convex class C(ψ) and starlike class S*(ψ), and the generalized Robertson class SPα(β). All derivations avoid Carathéodory coefficients cn; we only express the Taylor coefficients of Schwarz functions via Schur polynomials Fk(γ1,…,γk), then reduce each functional to a single-variable optimization, and construct explicit extremal Schwarz kernels as well as integral-form extremal univalent mappings.
SN - 2075-1680
ER -