Jean Mawhin – författare

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 particular, striking results were obtained in the classical problem of periodic solutions of Hamiltonian systems. This book provides a systematic presentation of the most basic tools of critical point theory: minimization, convex functions and Fenchel transform, dual least action principle, Ekeland variational principle, minimax methods, Lusternik- Schirelmann theory for Z2 and S1 symmetries, Morse theory for possibly degenerate critical points and non-degenerate critical manifolds. Each technique is illustrated by applications to the discussion of the existence, multiplicity, and bifurcation of the periodic solutions of Hamiltonian systems. Among the treated questions are the periodic solutions with fixed period or fixed energy of autonomous systems, the existence of subharmonics in the non-autonomous case, the asymptotically linear Hamiltonian systems, free and forced superlinear problems.Application of those results to the equations of mechanical pendulum, to Josephson systems of solid state physics and to questions from celestial mechanics are given. The aim of the book is to introduce a reader familiar to more classical techniques of ordinary differential equations to the powerful approach of modern critical point theory. The style of the exposition has been adapted to this goal. The new topological tools are introduced in a progressive but detailed way and immediately applied to differential equation problems. The abstract tools can also be applied to partial differential equations and the reader will also find the basic references in this direction in the bibliography of more than 500 items which concludes the book. ERSCHEIN

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 particular, striking results were obtained in the classical problem of periodic solutions of Hamiltonian systems. This book provides a systematic presentation of the most basic tools of critical point theory: minimization, convex functions and Fenchel transform, dual least action principle, Ekeland variational principle, minimax methods, Lusternik- Schirelmann theory for Z2 and S1 symmetries, Morse theory for possibly degenerate critical points and non-degenerate critical manifolds. Each technique is illustrated by applications to the discussion of the existence, multiplicity, and bifurcation of the periodic solutions of Hamiltonian systems. Among the treated questions are the periodic solutions with fixed period or fixed energy of autonomous systems, the existence of subharmonics in the non-autonomous case, the asymptotically linear Hamiltonian systems, free and forced superlinear problems. Application of those results to the equations of mechanical pendulum, to Josephson systems of solid state physics and to questions from celestial mechanics are given. The aim of the book is to introduce a reader familiar to more classical techniques of ordinary differential equations to the powerful approach of modern critical point theory. The style of the exposition has been adapted to this goal. The new topological tools are introduced in a progressive but detailed way and immediately applied to differential equation problems. The abstract tools can also be applied to partial differential equations and the reader will also find the basic references in this direction in the bibliography of more than 500 items which concludes the book. ERSCHEIN

This monograph explores the concept of the Brouwer degree and its continuing impact on the development of important areas of nonlinear analysis.

This monograph explores the concept of the Brouwer degree and its continuing impact on the development of important areas of nonlinear analysis.

This volume contains the texts of four courses given by the authors at a summer school that sought to present the growing field of topological methods in the theory of ordinary differential equations (in finite and infinite dimension), and to provide a forum for discussion of the wide variety of mathematical tools which are involved. The topics covered range from the extensions of the Lefschetz fixed point and the fixed point index on ANRs, to the theory of parity of one-parameter families of Fredholm operators, and from the theory of coincidence degree for mappings on Banach spaces to homotopy methods for continuation principles.

This volume contains the notes from five lecture courses devoted to nonautonomous differential systems, in which appropriate topological and dynamical techniques were described and applied to a variety of problems.

Indispensable for understanding Henri Poincaré's vast activity in the mathematical sciences. Provides new sources revealing Poincaré's involvement as president of the "Commission permanente du Répertoire bibliographique des sciences mathématiques" as an actor in the "Dreyfus Affair," and on his links with the editors of the major mathematical journals.The letters, many of which are unpublished, are fully annotated with an emphasis on the academic, cultural and technical contexts. An introduction underlines the lessons that can be drawn from the reading of these correspondences on Poincaré's position in the mathematical and academic communities. Three indexes facilitate the reading.Le volume de la correspondance de Poincaré consacré à ses échanges avec les mathématiciens permet de suivre son investissement dans le champ des sciences mathématiques de ses débuts comme étudiant brillant et prometteur préparant une thèse jusqu’à ses derniers jours, où devenu une icone pourla communauté mathématique depuis de longues années, sa correspondance traduit autant son activité dans la recherche que son implication dans les questions académiques, institutionnelles et organisationnelles. Les questions liées à la théorie des équations différentielles et l’entreprise du Répertoire bibliographique des sciences mathématiques ont suscité une activité épistolaire particulièrement sensible par le nombre de lettres qui y font allusion et par la diversité des correspondants qui abordent les questions de bibliographie mathématique. Les correspondances sont aussi l’occasion de multiples partages d’informations mathématiques, académiques et éditoriales.