32 research outputs found

    On the Bohr inequality

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    The Bohr inequality, first introduced by Harald Bohr in 1914, deals with finding the largest radius rr, 0<r<10<r<1, such that ∑n=0∞∣an∣rn≤1\sum_{n=0}^\infty |a_n|r^n \leq 1 holds whenever ∣∑n=0∞anzn∣≤1|\sum_{n=0}^\infty a_nz^n|\leq 1 in the unit disk D\mathbb{D} of the complex plane. The exact value of this largest radius, known as the \emph{Bohr radius}, has been established to be 1/3.1/3. This paper surveys recent advances and generalizations on the Bohr inequality. It discusses the Bohr radius for certain power series in D,\mathbb{D}, as well as for analytic functions from D\mathbb{D} into particular domains. These domains include the punctured unit disk, the exterior of the closed unit disk, and concave wedge-domains. The analogous Bohr radius is also studied for harmonic and starlike logharmonic mappings in D.\mathbb{D}. The Bohr phenomenon which is described in terms of the Euclidean distance is further investigated using the spherical chordal metric and the hyperbolic metric. The exposition concludes with a discussion on the nn-dimensional Bohr radius

    Integral Means and Arc length of Starlike Log-harmonic Mappings

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    We use star functions to determine the integral means for starlike log-harmonic mappings. Moreover, we include the upper bound for the arc length of starlike log-harmonic mappings

    On the univalence of the log-biharmonic mappings

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    AbstractIn this paper, we establish the univalence and starlikeness connection between log-biharmonic mappings and logharmonic mappings

    Gaussian curvature of minimal surface over a wedge

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    A geometric criterion for decomposition and multivalence

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