The descending flow method and existence of solutions for a class of elliptic equations
The authors minimize the energy functional on invariant sets by the minus gradient flow. They characterize invariant sets by this flow and identify disjoint invariant sets in which the functional is bounded from below, that leads to get to get three distinct solutions: a positive, a negative and a sign-changing one.
scientific article; zbMATH DE number 6526833
scientific article