Many years have passed since the ?rst edition. However, the encouragements of various readers and friends have persuaded us to write this third edition. During these years, Riemannian Geometry has undergone many dramatic - velopments. Here is not the place to relate them. The reader can consult for instance the recent book [Br5]. of our mentor Marcel Berger. However,R- mannian Geometry is not only a fascinating ?eld in itself. It has proved to be a precious tool in other parts of mathematics. In this respect, we can quote the major breakthroughs in four-dimensional topology which occurred in the eighties and the nineties of the last century (see for instance [L2]). These have been followed, quite recently, by a possibly successful approach to the Poincar´ e conjecture. In another direction, Geometric Group Theory, a very active ?eld nowadays (cf. [Gr6]), borrows many ideas from Riemannian or metric geometry. Butletusstophoggingthelimelight.Thisisjustatextbook.Wehopethatour point of view of working intrinsically with manifolds as early as possible, and testingeverynewnotiononaseriesofrecurrentexamples(seetheintroduction to the ?rst edition for a detailed description), can be useful both to beginners and to mathematicians from other ?elds, wanting to acquire some feeling for the subject.
From the reviews of the third edition:
"This new edition maintains the clear written style of the original, including many illustrations examples and exercises (most with solutions)." (Joseph E. Borzellino, Mathematical Reviews, 2005)
"This book based on graduate course on Riemannian geometry covers the topics of differential manifolds, Riemannian metrics, connections, geodesics and curvature, with special emphasis on the intrinsic features of the subject. Classical results are treated in detail. contains numerous exercises with full solutions and a series of detailed examples which are picked up repeatedly to illustrate each new definition or property introduced. For this third edition, some topics have been added and worked out in the same spirit." (L'ENSEIGNEMENT MATHEMATIQUE, Vol. 50, (3-4), 2004)
"This book is based on a graduate course on Riemannian geometry and analysis on manifolds that was held in Paris. Classical results on the relations between curvature and topology are treated in detail. The book is almost self-contained, assuming in general only basic calculus. It contains nontrivial exercises with full solutions at the end. Properties are always illustrated by many detailed examples." (EMS Newsletter, December 2005)
"The guiding line of this by now classic introduction to Riemannian geometry is an in-depth study of each newly introduced concept on the basis of a number of reoccurring well-chosen examples . The book continues to be an excellent choice for an introduction to the central ideas of Riemannian geometry." (M. Kunzinger, Monatshefte für Mathematik, Vol. 147 (1), 2006)Inhalt
1 Differential manifolds.- 1.A From submanifolds to abstract manifolds.- 1.A.1 Submanifolds of Euclidean spaces.- 1.A.2 Abstract manifolds.- 1.A.3 Smooth maps.- 1.B The tangent bundle.- 1.B.1 Tangent space to a submanifold of Rn+k.- 1.B.2 The manifold of tangent vectors.- 1.B.3 Vector bundles.- 1.B.4 Tangent map.- 1.C Vector fields.- 1.C.1 Definitions.- 1.C.2 Another definition for the tangent space.- 1.C.3 Integral curves and flow of a vector field.- 1.C.4 Image of a vector field by a diffeomorphism.- 1.D Baby Lie groups.- 1.D.1 Definitions.- 1.D.2 Adjoint representation.- 1.E Covering maps and fibrations.- 1.E.1 Covering maps and quotients by a discrete group.- 1.E.2 Submersions and fibrations.- 1.E.3 Homogeneous spaces.- 1.F Tensors.- 1.F.1 Tensor product (a digest).- 1.F.2 Tensor bundles.- 1.F.3 Operations on tensors.- 1.F.4 Lie derivatives.- 1.F.5 Local operators, differential operators.- 1.F.6 A characterization for tensors.- 1.G. Differential forms.- 1.G.1 Definitions.- 1.G.2 Exterior derivative.- 1.G.3 Volume forms.- 1.G.4 Integration on an oriented manifold.- 1.G.5 Haar measure on a Lie group.- 1.H Partitions of unity.- 2 Riemannian metrics.- 2.A Existence theorems and first examples.- 2.A.1 Basic definitions.- 2.A.2 Submanifolds of Euclidean or Minkowski spaces.- 2.A.3 Riemannian submanifolds, Riemannian products.- 2.A.4 Riemannian covering maps, flat tori.- 2.A.5 Riemannian submersions, complex projective space.- 2.A.6 Homogeneous Riemannian spaces.- 2.B Covariant derivative.- 2.B.1 Connections.- 2.B.2 Canonical connection of a Riemannian submanifold.- 2.B.3 Extension of the covariant derivative to tensors.- 2.B.4 Covariant derivative along a curve.- 2.B.5 Parallel transport.- 2.B.6 natural metric on the tangent bundle.- 2.C Geodesies.- 2.C.1 Definition, first examples.- 2.C.2 Local existence and uniqueness for geodesies, exponential map.- 2.C.3 Riemannian manifolds as metric spaces.- 2.C.4 An invitation to isosystolic inequalities.- 2.C.5 Complete Riemannian manifolds, Hopf-Rinow theorem.- 2.C.6 Geodesies and submersions, geodesies of PnC.- 2.C.7 Cut-locus.- 2.C.8 The geodesic flow.- 2.D A glance at pseudo-Riemannian manifolds.- 2.D.1 What remains true?.- 2.D.2 Space, time and light-like curves.- 2.D.3 Lorentzian analogs of Euclidean spaces, spheres and hegeode spaces.- 2.D.4 (In)completeness.- 2.D.5 The Schwarzschild model.- 2.D.6 Hyperbolicity versus ellipticity.- 3 Curvature.- 3.A. The curvature tensor.- 3.A.1 Second covariant derivative.- 3.A.2 Algebraic properties of the curvature tensor.- 3.A.3 Computation of curvature: some examples.- 3.A.4 Ricci curvature, scalar curvature.- 3.B. First and second variation.- 3.B.1 Technical preliminaries.- 3.B.2 First variation formula.- 3.B.3 Second variation formula.- 3.C. Jacobi vector fields.- 3.C.1 Basic topics about second derivatives.- 3.C.2 Index form.- 3.C.3 Jacobi fields and exponential map.- 3.C.4 Applications.- 3.D. Riemannian submersions and curvature.- 3.D.1 Riemannian submersions and connections.- 3.D.2 Jacobi fields of PnC.- 3.D.3 O'Neill's formula.- 3.D.4 Curvature and length of small circles. Application to Riemannian submersions.- 3.E. The behavior of length and energy in the neighborhood of a geodesic.- 3.E.1 Gauss lemma.- 3.E.2 Conjugate points.- 3.E.3 Some properties of the cut-locus.- 3.F Manifolds with constant sectional curvature.- 3.G Topology and curvature: two basic results.- 3.G.1 Myers' theorem.- 3.G.2 Cartan-Hadamard's theorem.- 3.H. Curvature and volume.- 3.H.1 Densities on a differentiable manifold.- 3.H.2 Canonical measure of a Riemannian manifold.- 3.H.3 Examples: spheres, hyperbolic spaces, complex projective spaces.- 3.H.4 Small balls and scalar curvature.- 3.H.5 Volume estimates.- 3.I. Curvature and growth of the fundamental group.- 3.I.1 Growth of finite type groups.- 3.I.2 Growth of the fundamental group of compact manifolds with negative curvature.- 3.J. Curvature and topology: some important results.- 3.J.1 Integral formulas.- 3.J.2 (Geo)metric methods.- 3.J.3 Analytic methods.- 3.J.4 Coarse point of view: compactness theorems.- 3.K. Curvature tensors and representations of the orthogonal group.- 3.K.1 Decomposition of the space of curvature tensors.- 3.K.2 Conformally flat manifolds.- 3.K.3 The Second Bianchi identity.- 3.L. Hyperbolic geometry.- 3.L.1 Introduction.- 3.L.2 Angles and distances in the hyperbolic plane.- 3.L.3 Polygons with many right angles.- 3.L.4 Compact surfaces.- 3.L.5 Hyperbolic trigonometry.- 3.L.6 Prescribing constant negative curvature.- 3.L.7 A few words about higher dimension.- 3.M. Conformai geometry.- 3.M.2 Introduction.- 3.M.3 The Möbius group.- 3.M.4 Conformai, elliptic and hyperbolic geometry.- 4 Analysis on manifolds.- 4.A. Manifolds with boundary.- 4.A.1 Introduction.- 4.A.2 Stokes theorem and integration by parts.- 4.B. Bishop inequality.- 4.B.1 Some commutation formulas.- 4.B.2 Laplacian of the distance function.- 4.B.3 Another proof of Bishop's inequality.- 4.B.4 Heintze-Karcher inequality.- 4.C. Differential forms and cohomology.- 4.C.1 The de Rham complex.- 4.C.2 Differential operators and their formal adjoints.- 4.C.3 The Hodge-de Rham theorem.- 4.C.4 A second visit to the Bochner method.- 4.D. Basic spectral geometry.- 4.D.1 The Laplace operator and the wave equation.- 4.D.2 Statement of basic results on the spectrum.- 4.E. Some examples of spectra.- 4.E.1 Introduction.- 4.E.2 The spectrum of flat tori.- 4.E.3 Spectrum of (Sn, can).- 4.F The minimax principle.- 4.G Eigenvalues estimates.- 4.G.1 Introduction.- 4.G.2 Bishop's inequality and coarse estimates.- 4.G.3 Some consequences of Bishop's theorem.- 4.G.4 Lower bounds for the first eigenvalue.- 4.H. Paul Levy's isoperimetric inequality.- 4.H.1 The statement.- 4.H.2 The proof.- 5 Riemannian submanifolds.- 5.A. Curvature of submanifolds.- 5.A.1 Second fundamental form.- 5.A.2 Curvature of hypersurfaces.- 5.A.3 Application to explicit computations of curvatures.- 5.B Curvature and convexity.- 5.C Minimal surfaces.- 5.C.1 First results.- 5.C.2 Surfaces with constant mean curvature.- A Some extra problems.- B Solutions of exercises.- List of figures.