FACHGEB The last decade has seen a tremendous development in critical point theory in
infinite dimensional spaces and its application to nonlinear boundary value problems. In …

This textbook is a completely revised, updated, and expanded English edition of the
important Analyse fonctionnelle (1983). In addition, it contains a wealth of problems and …

This review is devoted to the study of stationary solutions of linear and nonlinear equations
from relativistic quantum mechanics, involving the Dirac operator. The solutions are found as …

“… nothing at all takes place in the universe in which some rule of maximum or minimum
does not appear.” So said Euler in the eighteenth century. The statement may strike us as …

In the case of completely integrable systems, periodic solutions are found by inspection. For
nonintegrable systems, such as the three-body problem in celestial mechanics, they are …

Nonlinear analysis has developed rapidly in the last three decades. Theories, techniques
and results in many different branches of mathematics have been combined in solving …

One-dimensional variational problems have been somewhat neglected in the literature on
calculus of variations, as authors usually treat minimal problems for multiple integrals which …

A variational principle of a minimax nature is developed and used to prove the existence of
critical points for certain variational problems which are indefinite. The proofs are carried out …

Symplectic topology and hamiltonian dynamics Page 1 Séminaire Équations aux dérivées
partielles – École Polytechnique I. EKELAND H. HOFER Symplectic topology and …

In this paper we study existence problems for equations of the form in a real Hilbert space H.
Here A is a self-adjoint linear operator, and F is a potential operator, mapping H …