Electronic Journal of Differential Equations, Vol. 2024 (2024), No. 29, pp. 1-20. Title: Normalized ground state of a mixed dispersion nonlinear Schrodinger equation with combined power-type nonlinearities Authors: Zhouji Ma (Northeast Normal Univ., Changchun, Jilin, China) Xiaojun Chang (Northeast Normal Univ., Changchun, Jilin, China) Zhaosheng Feng (Univ. of Texas Rio Grande Valley, Edinburg, TX, USA) Abstract: We study the existence of normalized ground state solutions to a mixed dispersion fourth-order nonlinear Schrodinger equation with combined power-type nonlinearities. By analyzing the subadditivity of the ground state energy with respect to the prescribed mass, we employ a constrained minimization method to establish the existence of ground state that corresponds to a local minimum of the associated functional. Under certain conditions, by studying the monotonicity of ground state energy as the mass varies, we apply the constrained minimization arguments on the Nehari-Pohozaev manifold to prove the existence of normalized ground state solutions. Submitted November 18, 2023. Published April 01, 2024 Math Subject Classifications: 35Q55, 31B30, 35J30. Key Words: Normalized solutions; Schrodinger equation; Lagrange multiplier; ground states; Nehari-Pohozaev manifold.