Dhara, AnulekhaAnulekhaDharaLuc, Dinh TheDinh TheLucTinh, Phan NhatPhan NhatTinh2025-09-042025-09-042012-01-010866-7179https://d8.irins.org/handle/IITG2025/29637To study the su ciency of an optimization problem, one either imposes some convexity assumptions or consider second order optimality conditions. In this paper we establish second order optimality conditions for nonsmooth optimization problems by considering second order approximations of the functions involved and by introducing the concept of second order tangentiability.en-USSecond order tangent sets; second order approximations; second order optimality conditions; tangentiability; minimax problemArticlepp. 201–229Article123456789/552