Semnan University International Journal of Nonlinear Analysis and Applications 2008-6822 2026 01 02 Subclasses of bi-univalent functions connected to the normalized error function 10402 10.22075/ijnaa.2025.34251.5111 EN Aya Adel Al-romi Department of Mathematics, Faculty of Science, Al al-Bayt University, Mafraq, Jordan Basem Aref Frasin Department of Mathematics, Faculty of Science, Al al-Bayt University, Mafraq, Jordan Journal Article 2024 05 26 In this paper, we introduce two new subclasses of the function class $\Sigma$ of bi-univalent functions connected to the normalized error function. Also, we find estimates on the coefficients $|a_{2}|$ and $|a_{3}|$ for functions in these new subclasses. Furthermore, the Fekete-Szeg\"{o} problem for these subclasses is solved. A number of new results are shown to follow upon specializing the parameters involved in our main results. Analytic and univalent functions Bi-Univalent functions starlike and convex functions error function coefficients bounds https://ijnaa.semnan.ac.ir/article_10402_f9d3a954de63277730a1c66d8b38dee3.pdf