Altınkaya, Şahsene2023-03-092023-03-0920220920-4741https://doi.org/10.52547/ijmsi.17.1.207The purpose of the present paper is to introduce a class Dn ?;?C0(?) of bi-concave functions defined by Al-Oboudi differential op erator. We find estimates on the Taylor-Maclaurin coefficients |a2| and |a3| for functions in this class. Several consequences of these results are also pointed out in the form of corollaries.enBi-concave functionsAl-Oboudi differential operatorCoefficient estimatesArticle10.52547/ijmsi.17.1.2072-s2.0-85129946824Q1WOS:000798350900017Q1