On close-to-convex functions of complex order

The class S*(b) of starlike functions of complex order b was introduced and studied by M.K. Aouf and M.A. Nasr. The authors using the Ruscheweyh derivatives introduce the class K(b) of functions close-to-convex of complex order b, b≠0 and its generalization, the classes Kn(b) where n is a nonnegativ...

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Main Authors: H. S. Al-Amiri, Thotage S. Fernando
Format: Article
Language:English
Published: Wiley 1990-01-01
Series:International Journal of Mathematics and Mathematical Sciences
Subjects:
Online Access:http://dx.doi.org/10.1155/S0161171290000473
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author H. S. Al-Amiri
Thotage S. Fernando
author_facet H. S. Al-Amiri
Thotage S. Fernando
author_sort H. S. Al-Amiri
collection DOAJ
description The class S*(b) of starlike functions of complex order b was introduced and studied by M.K. Aouf and M.A. Nasr. The authors using the Ruscheweyh derivatives introduce the class K(b) of functions close-to-convex of complex order b, b≠0 and its generalization, the classes Kn(b) where n is a nonnegative integer. Here S*(b)⊂K(b)=K0(b). Sharp coefficient bounds are determined for Kn(b) as well as several sufficient conditions for functions to belong to Kn(b). The authors also obtain some distortion and covering theorems for Kn(b) and determine the radius of the largest disk in which every f∈Kn(b) belongs to Kn(1). All results are sharp.
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series International Journal of Mathematics and Mathematical Sciences
spelling doaj-art-edb3d162f90742bca28970e53c9a36cc2025-02-03T06:13:14ZengWileyInternational Journal of Mathematics and Mathematical Sciences0161-17121687-04251990-01-0113232133010.1155/S0161171290000473On close-to-convex functions of complex orderH. S. Al-Amiri0Thotage S. Fernando1Department of Mathematics and Statistics, Bowling Green State University, Bowling Green 43403, OH, USADepartment of Mathematics and Statistics, Bowling Green State University, Bowling Green 43403, OH, USAThe class S*(b) of starlike functions of complex order b was introduced and studied by M.K. Aouf and M.A. Nasr. The authors using the Ruscheweyh derivatives introduce the class K(b) of functions close-to-convex of complex order b, b≠0 and its generalization, the classes Kn(b) where n is a nonnegative integer. Here S*(b)⊂K(b)=K0(b). Sharp coefficient bounds are determined for Kn(b) as well as several sufficient conditions for functions to belong to Kn(b). The authors also obtain some distortion and covering theorems for Kn(b) and determine the radius of the largest disk in which every f∈Kn(b) belongs to Kn(1). All results are sharp.http://dx.doi.org/10.1155/S0161171290000473starlike functionsclose-to-convex functions of complex orderRuscheweyh derivativesHadamard product.
spellingShingle H. S. Al-Amiri
Thotage S. Fernando
On close-to-convex functions of complex order
International Journal of Mathematics and Mathematical Sciences
starlike functions
close-to-convex functions of complex order
Ruscheweyh derivatives
Hadamard product.
title On close-to-convex functions of complex order
title_full On close-to-convex functions of complex order
title_fullStr On close-to-convex functions of complex order
title_full_unstemmed On close-to-convex functions of complex order
title_short On close-to-convex functions of complex order
title_sort on close to convex functions of complex order
topic starlike functions
close-to-convex functions of complex order
Ruscheweyh derivatives
Hadamard product.
url http://dx.doi.org/10.1155/S0161171290000473
work_keys_str_mv AT hsalamiri onclosetoconvexfunctionsofcomplexorder
AT thotagesfernando onclosetoconvexfunctionsofcomplexorder