Preface |
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vii | |
About the Author |
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xi | |
Acknowledgments |
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xiii | |
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1 Basics on Commutative Algebra |
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1 | (54) |
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1.1 Ideals and Operations on Ideals |
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2 | (2) |
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4 | (1) |
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5 | (8) |
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1.3.1 Polynomials in D[ x], where D a UFD |
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5 | (3) |
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1.3.2 The case D = Ka field |
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8 | (1) |
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1.3.3 Resultant of two polynomials in D[ x] |
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9 | (3) |
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1.3.4 Resultant in D[ x1,...,xn] and elimination |
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12 | (1) |
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1.4 Noetherian Rings and the Hilbert Basis Theorem |
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13 | (3) |
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1.5 R-Modules, R-Algebras and Finiteness Conditions |
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16 | (3) |
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19 | (2) |
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21 | (2) |
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23 | (4) |
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1.9 Tensor Products of R-Modules and of R-Algebras |
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27 | (4) |
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1.9.1 Restriction and extension of scalars |
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29 | (1) |
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1.9.2 Tensor product of algebras |
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30 | (1) |
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1.10 Graded Rings and Modules, Homogeneous Ideals |
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31 | (11) |
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1.10.1 Homogeneous polynomials |
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35 | (6) |
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1.10.2 Graded modules and graded morphisms |
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41 | (1) |
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42 | (6) |
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1.11.1 Local rings and localization |
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46 | (2) |
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1.12 Krull-Dimension of a Ring |
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48 | (7) |
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52 | (3) |
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55 | (24) |
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2.1 Algebraic Affine Sets and Ideals |
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55 | (15) |
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2.2 Hilbert "Nullstellensatz" |
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70 | (4) |
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2.3 Some Consequences of Hilbert "Nullstellensatz" and of Elimination Theory |
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74 | (5) |
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74 | (1) |
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2.3.2 Intersections of affine plane curves |
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75 | (1) |
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76 | (3) |
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3 Algebraic Projective Sets |
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79 | (30) |
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3.1 Algebraic Projective Sets |
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80 | (3) |
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3.2 Homogeneous "Hilbert Nullstellensatz" |
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83 | (3) |
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3.3 Fundamental Examples and Remarks |
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86 | (23) |
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86 | (1) |
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3.3.2 Coordinate linear subspaces |
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87 | (1) |
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3.3.3 Hyperplanes and the dual projective space |
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87 | (1) |
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3.3.4 Fundamental affine open sets (or affine charts) of Fn |
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87 | (2) |
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3.3.5 Projective closure of affine sets |
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89 | (2) |
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3.3.6 Projective subspaces and their ideals |
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91 | (3) |
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3.3.7 Projective and affine subspaces |
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94 | (1) |
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3.3.8 Homographies, projectivities and affinities |
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95 | (4) |
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99 | (1) |
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3.3.10 Projective hypersurfaces and projective closure of affine hypersurfaces |
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99 | (1) |
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3.3.11 Proper closed subsets of P2 |
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100 | (1) |
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3.3.12 Affine and projective twisted cubics |
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101 | (5) |
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106 | (3) |
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4 Topological Properties and Algebraic Varieties |
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109 | (16) |
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4.1 Irreducible Topological Spaces |
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109 | (6) |
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4.1.1 Coordinate rings, ideals and irreducibility |
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112 | (2) |
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4.1.2 Algebraic varieties |
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114 | (1) |
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4.2 Noetherian Spaces: Irreducible Components |
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115 | (3) |
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4.3 Combinatorial Dimension |
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118 | (7) |
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123 | (2) |
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5 Regular and Rational Functions on Algebraic Varieties |
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125 | (24) |
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125 | (2) |
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127 | (3) |
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130 | (19) |
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5.3.1 Consequences of the fundamental theorem on regular and rational functions |
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141 | (2) |
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143 | (4) |
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147 | (2) |
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6 Morphisms of Algebraic Varieties |
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149 | (30) |
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149 | (2) |
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6.2 Morphisms with (Quasi) Affine Target |
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151 | (9) |
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6.3 Morphisms with (Quasi) Projective Target |
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160 | (4) |
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6.4 Local Properties of Morphisms: Affine Open Coverings of an Algebraic Variety |
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164 | (2) |
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6.5 Veronese Morphism: Divisors and Linear Systems |
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166 | (13) |
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6.5.1 Veronese morphism and consequences |
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171 | (3) |
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6.5.2 Divisors and linear systems |
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174 | (3) |
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177 | (2) |
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7 Products of Algebraic Varieties |
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179 | (16) |
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7.1 Products of Affine Varieties |
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179 | (3) |
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7.2 Products of Projective Varieties |
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182 | (6) |
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7.2.1 Segre morphism and the product of projective spaces |
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184 | (2) |
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7.2.2 Products of projective varieties |
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186 | (2) |
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7.3 Products of Algebraic Varieties |
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188 | (1) |
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7.4 Products of Morphisms |
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189 | (2) |
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7.5 Diagonals, Graph of a Morphism and Fiber-Products |
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191 | (4) |
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193 | (2) |
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8 Rational Maps of Algebraic Varieties |
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195 | (22) |
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8.1 Rational and Birational Maps |
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195 | (10) |
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8.1.1 Some properties and some examples of (bi)rational maps |
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199 | (6) |
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8.2 Unirational and Rational Varieties |
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205 | (12) |
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8.2.1 Stereographic projection of a rank-four quadric surface |
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206 | (2) |
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208 | (1) |
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8.2.3 Blow-up of Pn at a point |
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209 | (3) |
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8.2.4 Blow-ups and resolution of singularities |
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212 | (3) |
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215 | (2) |
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9 Completeness of Projective Varieties |
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217 | (8) |
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9.1 Complete Algebraic Varieties |
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217 | (2) |
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9.2 The Main Theorem of Elimination Theory |
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219 | (6) |
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9.2.1 Consequences of the main theorem of elimination theory |
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221 | (1) |
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222 | (3) |
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10 Dimension of Algebraic Varieties |
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225 | (16) |
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10.1 Dimension of an Algebraic Variety |
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225 | (5) |
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10.2 Comparison on Various Definitions of "Dimension" |
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230 | (2) |
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10.3 Dimension and Intersections |
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232 | (3) |
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10.4 Complete Intersections |
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235 | (6) |
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239 | (2) |
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11 Fiber-Dimension: Semicontinuity |
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241 | (8) |
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11.1 Fibers of a Dominant Morphism |
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241 | (3) |
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244 | (5) |
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246 | (3) |
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12 Tangent Spaces: Smoothness of Algebraic Varieties |
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249 | (16) |
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12.1 Tangent Space at a Point of an Affine Variety: Smoothness |
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249 | (4) |
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12.2 Tangent Space at a Point of a Projective Variety: Smoothness |
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253 | (2) |
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12.3 Zariski Tangent Space of an Algebraic Variety: Intrinsic Definition of Smoothness |
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255 | (10) |
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263 | (2) |
Solutions to Exercises |
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265 | (30) |
Bibliography |
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295 | (2) |
Index |
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297 | |