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Since its first appearance as a set of lecture notes published by the Courant Institute in 1974, this book served as an introduction to various subjects in nonlinear functional analysis. The current edition is a reprint of these notes, with added bibliographic references. Topological and analytic methods are developed for treating nonlinear ordinary and partial differential equations. The first two chapters of the book introduce the notion of topological degree and develop its basic properties. These properties are used in later chapters in the discussion of bifurcation theory (the possible branching of solutions as parameters vary), including the proof of Rabinowitz's global bifurcation theorem. Stability of the branches is also studied.The book concludes with a presentation of some generalized implicit function theorems of Nash-Moser type with applications to Kolmogorov-Arnold-Moser theory and to conjugacy problems. After more than 20 years, this book continues to be an excellent graduate level textbook and a useful supplementary course text.

Especially among Japanese mathematicians Mitio Nagumo (1905-1995) is regarded as one of the greatest pioneers in research on differential equations. However, so far most of his papers have only been published in Japanese journals and were unavailable in the West. This Collected Papers volume contains practically all mathematical papers Nagumo wrote in languages other than Japanese and will be a basic reference volume and essential working tool for every library and for many active mathematicians in differential equations, topology and differential geometry. In addition, papers that were originally published in Japanese were translated especially for this edition. There are three main sections in this book, devoted to ordinary differential equations, partial differential equations and other equations. Each section is accompanied by a detailed commentary provided by the editors.

S. Agmon: Asymptotic formulas with remainder estimates for eigenvalues of elliptic operators.- J. Bokobza-Haggiag: Une definition globale des operateurs pseudo-differentiels sur une variete differentiable.- L. Boutet de Monvel: Pseudo-differential operators and analytic function.- A. Calderon: A priori estimates for singular integral operators.- B.F. Jones: Characterization of spaces of Bessel potentials related to the heat equation.- J.J. Kohn: Pseudo-differential operators and non-elliptic problems.- R.T. Seeley: Topics in pseudo-differential operators.- I.M. E. Shamir: Boundary value problems for elliptic convolution systems.- Singer: Elliptic operators on manifolds.