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  • Yayın
    Subclass of m-quasiconformal harmonic functions in association with Janowski starlike functions
    (Elsevier Science Inc, 2018-02-15) Sakar, Fethiye Müge; Aydoğan, Seher Melike
    Let's take f(z) = h (z) + <(g(z))over bar> which is an univalent sense-preserving harmonic functions in open unit disc D = {z : vertical bar z vertical bar < 1}. If f (z) fulfills vertical bar w(z)vertical bar = |g'(z)/h'(z)vertical bar < m, where 0 <= m < 1, then f(z) is known m-quasiconformal harmonic function in the unit disc (Kalaj, 2010) [8]. This class is represented by S-H(m).The goal of this study is to introduce certain features of the solution for non- linear partial differential equation <(f)over bar>((z) over bar) = w(z)f(z) when vertical bar w(z)vertical bar < m, w(z) (sic) m(2)(b(1)-z)/m(2)-b(1)z, h(z) is an element of S*(A, B). In such case S*(A, B) is known to be the class for Janowski starlike functions. We will investigate growth theorems, distortion theorems, jacobian bounds and coefficient ineqaulities, convex combination and convolution properties for this subclass.
  • Yayın
    Notes on starlike log-harmonic functions of order α
    (2013) Aydoğan, Seher Melike; Duman, Emel Yavuz; Owa, Shigeyoshi
    For log-harmonic functions f(z) = zh(z)g(z) in the open unit disk U, two subclasses H*LH(α) and G*LH(α) of S*LH(α) consisting of all starlike log-harmonic functions of order α (0 ≤ α < 1) are considered. The object of the present paper is to discuss some coefficient inequalities for h(z) and g(z).Mathematics Subject Classification: Primary 30C55, Secondary 30C45.
  • Yayın
    Some inequalities which hold for starlike log-harmonic mappings of order alpha
    (Eudoxus Press, LLC., 2014-04) Özkan Uçar, Hatice Esra; Aydoğan, Seher Melike
    Let H(D) be the linear space of all analytic functions defined on the open disc D = {z vertical bar vertical bar z vertical bar < 1}. A log-harmonic mappings is a solution of the nonlinear elliptic partial differential equation <(f)over bar>((z) over bar) = w (f) over bar /f f(z) where w(z) is an element of H(D) is second dilatation such that vertical bar w(z)vertical bar < 1 for all z is an element of D. It has been shown that if f is a non-vanishing log-harmonic mapping, then f can be expressed as f(z) = h(z)<(g(z))over bar> where h(z) and g(z) are analytic function in D. On the other hand, if f vanishes at z = 0 but it is not identically zero then f admits following representation f(z) = z vertical bar z vertical bar(2 beta) h(z)<(g(z))over bar> where Re beta > -1/2, h and g are analytic in D, g(0) = 1, h(0) not equal 0. Let f = z vertical bar z vertical bar(2 beta) h (g) over bar be a univalent log-harmonic mapping. We say that f is a starlike log-harmonic mapping of order alpha if partial derivative(arg f(re(i theta)))/partial derivative theta = Rezf(z)-(z) over barf((z) over bar)/f > alpha, 0 <= alpha < 1. (for all z is an element of U) and denote by S-lh*(alpha) the set of all starlike log-harmonic mappings of order alpha. The aim of this paper is to define some inequalities of starlike log-harmonic functions of order alpha (0 <= alpha <= 1).