Critical Point Theory Sandwich and Linking Systems

“Many problems arizing in science and engineering call for the solving of nonlinear ordinary differential equations or partial differential equations. These equations are difficult to solve, and there are few general techniques … to solve them. … This has motivated researchers to study critical points of functionals in order to solve the corresponding Euler equations. It has led to the development of several techniques to find critical points. This book is dedicated to the latest developments and applications of these techniques.” (Mohsen Timoumi,zbMATH 1462.35008, 2021)