Splitting subspaces and saddle points
Martin Schechter · Applicable Analysis · 1993
We prove a saddle point theorem for a functional using linking subsets of splitting subspaces. The values of the functional on one of the linking subsets do not have to be bounded away from those values on the other subset. Moreover, it does not matter which subspace is finite dimensional. Applications are given to boundary value problems for elliptic partial differential equations.