TY - JOUR JF - IJMSI JO - IJMSI VL - 17 IS - 1 PY - 2022 Y1 - 2022/4/01 TI - Bi-concave Functions Defined by Al-Oboudi Differential Operator TT - N2 - The purpose of the present paper is to introduce a class $D_{Sigma ;delta }^{n}C_{0}(alpha )$ of bi-concave functions defined by Al-Oboudi differential operator. We find estimates on the Taylor-Maclaurin coefficients $leftvert a_{2}rightvert $ and $leftvert a_{3}rightvert$ for functions in this class. Several consequences of these results are also pointed out in the form of corollaries. SP - 207 EP - 217 AU - Altinkaya, Ş. AD - Department of Mathematics, Beykent University, 34500, Istanbul, Turkey KW - Bi-concave functions KW - Al-Oboudi differential operator KW - Coefficient estimates. UR - http://ijmsi.ir/article-1-1408-en.html DO - 10.52547/ijmsi.17.1.207 ER -