Remarks on compactness conditions and their application
David G. Costa · Electronic Journal of Differential Equations · 2023
We review typical compactness conditions used in variational techniques and some of their properties, and the relationships between them. In particular, we provide some new insights into results related to the Palais-Smale and Cerami conditions, and their comparison. See also https://ejde.math.txstate.edu/special/02/c3/abstr.html