Introduction |
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xi | |
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1 Basic Concepts of Riemannian Geometry |
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1 | (26) |
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1.1 Moving frames: Levi-Civita connection, structure equations and curvatures |
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1 | (13) |
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1.1.1 Levi-Civita connection, first structure equation and covariant derivatives |
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1 | (5) |
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1.1.2 Second structure equation and the Riemann tensor |
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6 | (4) |
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1.1.3 Ricci, scalar and sectional curvatures |
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10 | (4) |
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1.2 General frame: everything with Christoffel symbols |
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14 | (5) |
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1.2.1 Levi-Civita connection and covariant derivatives revisited |
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14 | (1) |
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1.2.2 Riemann and Ricci curvatures revisited |
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15 | (1) |
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1.2.3 Covariant derivatives revisited, Hessian and Laplacian |
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16 | (3) |
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1.3 Back to moving frames: the decomposition of the curvature tensor |
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19 | (3) |
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1.4 Other curvatures: A, B, C |
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22 | (5) |
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2 Commutations and Variations |
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27 | (24) |
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27 | (6) |
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2.2 Variations of curvatures tensors and other geometric quantities |
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33 | (18) |
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33 | (6) |
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2.2.2 Conformal deformations |
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39 | (6) |
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2.2.3 Aubin's deformation |
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45 | (6) |
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51 | (20) |
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51 | (6) |
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51 | (2) |
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53 | (4) |
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3.1.3 The Weyl-Schouten and Aubin theorems |
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57 | (1) |
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3.2 The case of dimension four |
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57 | (14) |
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3.2.1 Self-dual and anti-self-dual parts of W |
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58 | (1) |
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3.2.2 The Derdzinski basis |
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58 | (1) |
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59 | (6) |
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3.2.4 Integral identities and topology |
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65 | (2) |
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67 | (4) |
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71 | (38) |
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4.1 Old and new canonical metrics: algebraic and analytic conditions |
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71 | (6) |
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76 | (1) |
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4.2 Canonical metrics revisited: equivalent conditions |
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77 | (4) |
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4.3 The rigid classes: f, f, f and f |
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81 | (2) |
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83 | (6) |
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4.4.1 Rigidity and characterization results |
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83 | (4) |
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87 | (2) |
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4.5 The class f: a possible generalization of the Yamabe problem |
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89 | (13) |
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89 | (2) |
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91 | (1) |
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4.5.3 An existence result in Euclidean space |
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92 | (10) |
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4.6 Non-gradient canonical metrics |
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102 | (5) |
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104 | (1) |
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4.6.2 The classes X and X |
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104 | (1) |
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105 | (2) |
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107 | (1) |
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4.7 Final remarks and open problems |
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107 | (2) |
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5 Critical Metrics of Riemannian Functionals |
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109 | (26) |
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5.1 The Einstein--Hilbert functional |
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109 | (3) |
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5.2 Quadratic curvature functionals |
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112 | (3) |
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112 | (1) |
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5.2.2 Remarks on two special cases |
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113 | (2) |
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5.3 Some rigidity results for quadratic functionals |
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115 | (20) |
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5.3.1 The Euler-Lagrange equations |
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118 | (2) |
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5.3.2 Proofs of Theorem 5.4 and Theorem 5.5 |
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120 | (6) |
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5.3.3 Proof of Theorem 5.7 |
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126 | (2) |
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5.3.4 Proof of Theorem 5.8 |
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128 | (3) |
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5.3.5 The Euler-Lagrange equation for t,s |
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131 | (4) |
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6 Bochner-Weitzenbock Formulas and Applications |
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135 | (24) |
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6.1 A general Bochner-Weitzenbock formula |
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135 | (2) |
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135 | (1) |
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6.1.2 Dimension four and an integral identity |
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136 | (1) |
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137 | (8) |
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6.2.1 Harmonic Weyl and Einstein manifolds: the first Bochner-Weitzenbock formula |
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137 | (1) |
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6.2.2 Rigidity results for Einstein manifolds |
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138 | (2) |
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6.2.3 A general result on four-dimensional manifolds |
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140 | (5) |
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6.3 Higher-order Bochner-Weitzenbock formulas on Einstein manifolds |
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145 | (14) |
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145 | (4) |
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6.3.2 The second Bochner-Weitzenbock formula |
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149 | (1) |
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6.3.3 A rigidity result for Einstein manifolds |
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150 | (9) |
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7 Ricci Solitons: Selected Results |
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159 | (54) |
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161 | (6) |
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7.1.1 Fundamental formulas for Ricci solitons |
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161 | (4) |
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7.1.2 The tensor D and the integrability conditions |
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165 | (2) |
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7.2 Rigidity I: pointwise conditions |
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167 | (7) |
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7.2.1 Compact shrinkers with strictly positive sectional curvature |
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167 | (5) |
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7.2.2 Further results in the non-necessarily gradient case |
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172 | (2) |
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7.3 Rigidity II: integral conditions |
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174 | (17) |
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7.3.1 The compact case: integral pinching conditions |
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174 | (4) |
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7.3.2 The non-compact case: L1 conditions and integral curvature decay |
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178 | (13) |
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7.4 Rigidity III: vanishing conditions on the Weyl tensor |
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191 | (9) |
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7.4.1 A key integral formula |
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194 | (2) |
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7.4.2 Proof of the results |
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196 | (4) |
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7.5 Rigidity IV: Weyl scalars |
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200 | (13) |
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7.5.1 Weyl scalars on a Ricci soliton |
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202 | (3) |
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205 | (3) |
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208 | (5) |
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8 Existence Results of Canonical Metrics on Four-Manifolds |
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213 | (18) |
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8.1 A new variational problem: Weak harmonic Weyl metrics |
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213 | (4) |
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8.2 The Euler-Lagrange equation |
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217 | (2) |
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217 | (2) |
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8.2.2 The PDE for the conformal factor |
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219 | (1) |
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8.3 Existence of minimizers |
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219 | (12) |
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8.3.1 Proof of Theorem 8.2 |
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219 | (1) |
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8.3.2 Some preliminary results |
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220 | (1) |
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221 | (4) |
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225 | (3) |
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228 | (3) |
List of Symbols |
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231 | (2) |
Bibliography |
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233 | (10) |
Index |
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243 | |