Browsing by Author "Owa, Shigeyoshi"
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Publication Open Access A note on certain analytic functions(International Short Joint Research Workshop, Study on Calculus Operators in Univalent Function Theory, 2007, Research Institute for Mathematical Sciences, Kyoto University (RIMS), Kyoto, Japan, 2007) Nunokawa, M.; Owa, Shigeyoshi; POLATOĞLU, YAŞAR; 199370Publication Metadata only A Remark on multivalently convex and starlike functions(2007-01) Nunokawa, Mamoru; Owa, Shigeyoshi; Yavuz Duman, Emel; POLATOĞLU, YAŞAR; 199370; 111202Applying the result for certain analytic functions due to M. Nunokawa [Proc. Japan Acad. 68A, 152–153 (1992; Zbl 0773.30020)], some properties for multivalently convex and starlike functions ar discussed.Publication Embargo Coefficient inequalities for classes of uniformly starlike and convex functions(2006-01) Owa, Shigeyoshi; YAVUZ, EMEL; POLATOĞLU, YAŞAR; 199370; 111202In view of classes of uniformly starlike and convex functions in the open unit discUwhich was considered by S. Shams, S.R. Kulkarni and J.M. Jahangiri, some coefficient in-equalities for functions are discussedPublication Restricted Generalizations for Certain Bazilevic Functions(SEAMS - Southeast Asian Mathematical Society, 2021) YAVUZ, EMEL; DAYMAZ, TUĞBA; Owa, ShigeyoshiFor analytic functions f(z) in the open unit disk U, an interesting class A(alpha, beta, gamma) is considered. The object of the present paper is to discuss some properties for f(z) in the class A(alpha, beta, gamma) and the class A(alpha, beta, infinity) for gamma -> infinity.Publication Metadata only Multivalued p-valent starlike functions(2007) Çağlar, M.; Şen, A.; Owa, Shigeyoshi; YAVUZ, EMEL; POLATOĞLU, YAŞAR; 199370Publication Embargo Multivalued starlike functions of complex order(2008) Çağlar, Mert; Owa, Shigeyoshi; YAVUZ, EMEL; POLATOĞLU, YAŞAR; 199370; 111202Let S ∗ λ (1−b)(b 6= 0, complex) denote the class of functions f(z) = z+a2z 2+· · · analytic in the open unit disc D = {z ∈ CPublication Embargo Multivalued starlike functions of complex order(2008) Çağlar, Mert; Owa, Shigeyoshi; Şen, Arzu; YAVUZ, EMEL; POLATOĞLU, YAŞAR; 199370; 108339; 111202Let Aα be the class of functions f(z) = z α (z + a2z 2 + · · ·) which are analytic in the open unit disc U. For f(z) ∈ Aα using the fractional calculus, a subclass S ∗ α (1−b) which is the class of starlike functions of complex order (1−b) is introduced. The object of the present paper is to discuss some properties for f(z) belonging to the class S ∗ α (1 − b). 2000 Mathematics Subject Classification: 30C45Publication Embargo New characterization of the class of starlike functions(The Korean Mathematical Society, 2008) Owa, Shigeyoshi; YAVUZ, EMEL; POLATOĞLU, YAŞAR; 111202; 199370For analytic functions f(z) in the open unit disc D, an operator Nα(f(z)) relating with starlike functions is introduced. The object of the present paper is to discuss some properties of the operator Nα(f(z)).Publication Metadata only New subclasses of certain analytic functions(2010) Owa, Shigeyoshi; Yavuz Duman, Emel; Aydoğan, S. M.; POLATOĞLU, YAŞAR; 199370; 111202For certain analytic functions fiz) in the open unit disk U, two subclasses 7ia,S;g) and Q(a,(5;g) associated with some analytic function g{z). Some interesting sufficient conditions for fiz) to be in ^(Q,^;^ ) and Qia,6;g) and some necessary conditions for f{z) belonging to •?{a,S;g) and Q{a,S;g) are considered.Publication Metadata only Notes on certain analytic functions(SCIENTIFIC TECHNICAL RESEARCH COUNCIL TURKEY-TUBITAK, ATATURK BULVARI NO 221, KAVAKLIDERE, TR-06100 ANKARA, TURKEY, 2019) Owa, Shigeyoshi; YAVUZ, EMEL; 111202Let A(n) be the class of functions f(z) = a(n)z(n) + a(n+1)z(n+1) +...(n is an element of N), which are analytic in the open unit disk U, where a(n) not equal 0. For f(z) is an element of A(n), Miller and Mocanu in 1978 showed a very interesting result for f(z). Applying the result due to Miller and Mocanu, we would like to consider some new results for such functions. Our results in this paper are generalizations for results by Nunokawa in 1992.Publication Metadata only Notes on Certain Harmonic Starlike Mappings(9th International Symposium on Geometric Function Theory and Applications, GFTA, 2014) Yavuz Duman, Emel; Owa, Shigeyoshi; 111202Publication Embargo Notes on Starlike log-Harmonic Functions of Order alpha(2013) Aydoğan, Seher Melike; Yavuz Duman, Emel; Owa, Shigeyoshi; 35549; 111202For 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).Publication Embargo On Janowski starlike functions(Springer International Publishing Ag, Gewerbestrasse 11, Cham, Ch-6330, Switzerland, 2007) Çağlar, Mert; Şen, A.; Owa, Shigeyoshi; YAVUZ, EMEL; POLATOĞLU, YAŞAR; 108339; 199370; 111202For analytic functions f(z) in the open unit disc U with f(0) = 0 and f'(0) = 1, applying the fractional calculus for f(z), a new fractional operator D-lambda f(z) is introduced. Further, a new subclass F-lambda(*)(A, B) consisting of f(z) associated with Janowski function is defined. The objective of the present paper is to discuss some interesting properties of the class F-lambda(*)(A, B). Copyright (c) 2007.Publication Metadata only On lambda-fractional convex functions(2007) Owa, Shigeyoshi; YAVUZ, EMEL; POLATOĞLU, YAŞAR; 199370; 111202Publication Embargo On some alpha-convex functions(2008-06) Owa, Shigeyoshi; Acu, Mugur; Al-Oboudi, Fatima; Darus, Maslina; YAVUZ, EMEL; POLATOĞLU, YAŞAR; 199370; 111202In this paper, we define a general class of α-convex functions, denoted by MLβ,α(q), with respect to a convex domain D (q(z) ∈ Hu(U), q(0) = 1 , q(U) = D) contained in the right half plane by using the linear operator D β λ defined by D β λ : A → A , D β λ f(z) = z + X∞ j=2 (1 + (j − 1)λ) β ajz j , where β, λ ∈ R, β ≥ 0, λ ≥ 0 and f(z) = z+ X∞ j=2 ajz j . Regarding the class MLβ,α(q), we give a inclusion theorem and a transforming theorem, from which we may obtain many particular results.Publication Embargo On the improvement of Mocanu's conditions(Springer International Publishing, 2013-12) Nunokawa, M.; Owa, Shigeyoshi; Cho, N. E.; Sokół, J.; Yavuz Duman, EmelWe estimate |Arg{p(z)}| for functions of the form p(z)=1+a1z+a2z2+a3z3+⋯ in the unit disc D={z:|z|<1} under several assumptions. By using Nunokawa’s lemma, we improve a few of Mocanu’s results obtained by differential subordinations. Some applications for strongly starlikeness and convexity are formulated.Publication Embargo Partial sums of certain univalent functions(2012) Hayami, Toshio; Kuroki, Kazuo; Yavuz Duman, Emel; Owa, Shigeyoshi; 111202The partial sums f3(z) of some extermal functions for various classes S∗, K and R of starlike functions, convex functions and functions with positive real part in the open unit disk U, respectively, are discussed. In general, the partial sums can not preserve the same character as the initial functions. The object of the present paper is to discuss the radius problems for partial sums of some extremal functions for the classes S∗, K and R.Publication Embargo Properties of functions concerned with Caratheodory functions(2013) Nunokawa, Mamoru; Yavuz Duman, Emel; Owa, Shigeyoshi; 111202Let Pn denote the class of analytic functions p(z) of the form p(z) = 1+ cnzn + cn+1zn+1 + ... in the open unit disc U. Applying the result by S. S. Miller and P. T. Mocanu (J. Math. Anal. Appl. 65 (1978), 289–305), some interesting properties for p(z) concerned with Carath´eodory functions are discussed. Further, some corollaries of the results concerned with the result due to M. Obradović and S. Owa (Math. Nachr. 140 (1989), 97–102) are shown.Publication Embargo Reciprocal Classes Of P-Valently Spirallike And P-Valently Robertson Functions(Springer International Publishing Ag, Gewerbestrasse 11, Cham, Ch-6330, Switzerland, 2011) Uyanık, Neslihan; Owa, Shigeyoshi; Shiraishi, Hitoshi; POLATOĞLU, YAŞAR; TR199370; TR110824For p-valently spirallike and p-valently Robertson functions in the open unit disk U, reciprocal classes S-p(alpha, beta), and C-p(alpha, beta) are introduced. The object of the present paper is to discuss some interesting properties for functions f(z) belonging to the classes S-p(alpha, beta) and C-p(alpha, beta).Publication Metadata only Some Properties Of Analytic Functions Relating To The Miller And Mocanu Result(Pergamon-Elsevier Science Ltd, The Boulevard, Langford Lane, Kidlington, Oxford Ox5 1Gb, England, 2011-03) Yavuz Duman, Emel; Nunokawa, Mamoru; Owa, Shigeyoshi; Aydoğan, Melike; TR111202; TR35549Let P(alpha) be the class of analytic functions p(z) in the open unit disc U with p(0) = 1 and |arg p(z)| < pi/2 alpha (z is an element of U) for some real alpha > 0. The object of the present paper is to discuss some properties of p(z) in the class P(alpha). Furthermore, an example for our results is shown. (C) 2010 Elsevier Ltd. All rights reserved.