Radii of harmonic mapping with fixed second coefficients in the plane
DOI:
https://doi.org/10.24193/subbmath.2018.2.03Keywords:
Stable starlike functions, stable univalent function, stable convex function, radii problem.Abstract
In this paper we investigate the radii problem for harmonic functions with a fixed coefficient and determine the radii of univalence, stable starlikness, stable convexity, fully starlikness and fully convexity of order α for these type of functions. All results are sharp. Also these results generalize and improve some results in the literature.
Mathematics Subject Classification (2010): 30C45, 30C80.
References
Ali, R.M., Cho, N.E., Jain, N.K., Ravichandran, V., Radii of starlikeness and convexity of functions defined by subordination with fixed second coefficients, Filomat, 26(2012), 553-561.
Ali, R.M., Nagpal, S., Ravichandran, V., Second-order differential subordinations for analytic functions with fixed initial coefficient, Bull. Malays. Math. Sci. Soc., 34(2011), no. 2, 611-629.
Chen, Sh., Ponnusamy, S., Wang, X., Bloch constants and Landau’s theorems for planner p-harmonic mapping, J. Math. Anal. Appl., 373(2011), 102-110.
Chuaqui, M., Duren, P.L., Osgood, B., Curvature properties of planar harmonic map- pings, Comput. Methods Funct. Theory, 4(2004), no. 1, 127-142.
Clunie, J.G., Sheil-Small, T., Harmonic univalent functions, Ann. Acad. Sci. Fenn. Ser. A., 9(1984), 3-25.
Gangadharan, A., Ravichandran, V., Shanmugam, T.N., Radii of convexity and strong starlikeness for some classes of analytic functions, Journal of Mathematical Analysis and Applications, 211(1997), no. 1, 301-313.
Hernandez, R., Martin, M.J., Stable geometric properties of analytic and harmonic functions, Math. Proc. of the Cambridge Philosophical Soc., 155(2013), no. 2, 343-359.
Jahangiri, J.M., Coefficient bounds and univalence criteria for harmonic functions with negative coefficients, Ann. Univ. Mariae Curie-Shlodowska, sect. A, 59(1998), no. 2, 57-66.
Jahangiri, J.M., Harmonic functions starlike in the unit disk, J. Math. Anal. Appl., 235(1999), no. 2, 470-477.
Kalaj, D., Ponnusamy, S., Vuorinen, M., Radius of close-to-convexity of harmonic functions, Complex Var. Elliptic Equ, 59(2014), no. 4, 539-552.
Lewy, H., On the non-vanishing of the Jacobian in certain one-to-one mapping, Bull. Amer. Math. Soc., 24(10)(1936), 689-692.
Long, B.Y., Hang, H., Radii of harmonic mapping in the plane, J. Aust. Math. Soc., (2016), 1-7.
Ma, W., Minda, D., Uniformly convex functions, Ann. Polon. Math., 57(1992), 165-175. [14] Nagpal, S., Ravichandran, V., Fully starlike and convex harmonic mappings of order α, Ann. Polon. Math., 108(2012), 1-7.
Rajni, M., Nagpal, S., Ravichandran, V., Radii of starlikeness and convexity for analytic functions with fixed second coefficient satisfying certain coefficient inequalities, Kyungpook Mathematical Journal, 55(2015), no. 2, 395-410.
Ravichandran, V., Radii of starlikeness and convexity of analytic functions satisfying certain coefficient inequalities, Mathematica Slovaca, 64(2014), no. 1, 27-38.
Ravichandran, V., Khan, M.H., Silverman, H., Subramanian, K.G., Radius problems for a class of analytic functions, Demonstratio Math., 39(2006), no. 1, 67-74.
Ruscheweyh, St., Salinas, L., On the preservation of direction-convexity and Goodman- Saff Conjecture, Ann. Acad. Sci. Fenn. Ser. A I Math., 14(1989), 63-73.
Sheil-Small, T., Constants for plannar harmonic mapping, J. Lond. Math. Soc., 42(1990), no. 2, 237-248.
Wang, X.-T., Liang, X.-Q., Zhang, Y.-L., Precise coefficient for close-to-convex harmonic univalent mapping, J. Math. Anal. Appl., 263(2001), no. 2, 501-509.
Yamashita, S., Radii of univalence, starlikeness and convexity, Bull. Austral. Math. Soc., 25(1982), 453-457.
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