Log-harmonic coefficient conjecture

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Let f(z)=zh(z)g(z)‾∈SLhf(z)=zh(z)\overline{g(z)}\in\mathcal{S}_{Lh}, where hh and gg are given by the coefficient expansions in the source. Thus, for n≥1n\geq 1, ana_n and bnb_n denote the corresponding analytic and co-analytic coefficients. Log-harmonic coefficient conjecture. For all n≥1n\geq 1,

∣an∣≤2+1n,∣bn∣≤2−1n,∣an−bn∣≤2n.|a_n|\leq 2+\frac{1}{n},\qquad |b_n|\leq 2-\frac{1}{n},\qquad |a_n-b_n|\leq \frac{2}{n}.

This is proposed as an analogue of the analytic and harmonic Bieberbach conjectures. It is known for starlike log-harmonic mappings; the general case remains open.

References

Primary source

ZhiHong Liu and Saminathan Ponnusamy, “On univalent log-harmonic mappings”, arXiv:1905.10551 (2019).

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