Some Results Concerned with Hankel Determinant
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Authors: B. N. ORNEK
DOI: 10.46793/KgJMat2303.481O
Abstract:
In this paper, we discuss different versions of the boundary Schwarz lemma and Hankel determinant for ????
class. Also, for the function
f(z) = z + c2z2 + c3z3 + 
defined in the unit disc such that f ∈????(α), we
estimate a modulus of the angular derivative of f(z) function at the
boundary point z0 with f(z0) = 
and f′(z
0) = 
. That is, we shall
give an estimate below 
according to the first nonzero Taylor
coefficient of about two zeros, namely z = 0 and z1≠0. The sharpness of
this inequality is also proved.
Keywords:
Fekete-Szegö functional, Julia-Wolff lemma, Hankel determinant, analytic function, Schwarz lemma. angular derivative.
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