Coefficient bounds for a generalized subclass of bounded turning functions associated with Sigmoid function

Document Type : Research Paper


1 Department of Mathematics, Khalsa College, Amritsar-143001, Punjab, India

2 Department of Mathematics, G.N.D.U. College, Chungh-143304, Tarn-Taran(Punjab), India



In this paper, we introduce a subclass of analytic functions associated with the Sigmoid function and determine the upper bounds for various coefficient functionals such as  Fekete-Szego functional, second Hankel determinant, Zalcman functional and third Hankel determinant. Also, the concept is extended to two-fold and three-fold symmetric functions. The results proved earlier, follow as special cases of the results of this paper.


Articles in Press, Corrected Proof
Available Online from 08 March 2023
  • Receive Date: 11 January 2023
  • Revise Date: 19 February 2023
  • Accept Date: 24 February 2023
  • First Publish Date: 08 March 2023