Preface |
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vii | |
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1 | (8) |
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1.1 What are Davenport-Zannier polynomials |
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1 | (3) |
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1.2 Dessins d'enfants and Galois theory |
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4 | (1) |
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1.3 What are weighted trees |
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5 | (4) |
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Chapter 2 Dessins d'enfants: from polynomials through Belyi functions to weighted trees |
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9 | (10) |
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2.1 Rational function ƒ = P/R and its critical values |
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9 | (2) |
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2.2 Dessins d'enfants and Belyi functions |
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11 | (3) |
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14 | (2) |
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2.4 Additional remarks about weighted trees |
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16 | (3) |
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Chapter 3 Existence theorem |
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19 | (8) |
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3.1 Readability of coverings |
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19 | (1) |
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20 | (1) |
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3.3 Stitching several trees to get one: the case gcd(α, β) = 1 |
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20 | (2) |
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22 | (1) |
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3.5 Weak bound: polynomials and cacti |
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22 | (3) |
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3.6 Proof of the weak bound |
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25 | (2) |
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Chapter 4 Recapitulation and perspectives |
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27 | (2) |
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Chapter 5 Classification of unitrees |
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29 | (30) |
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5.1 Statement of the main result |
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29 | (7) |
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36 | (3) |
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39 | (2) |
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5.4 Trees with repeating branches of height 2 |
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41 | (4) |
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5.5 Trees with repeating branches of the type (1, s, s + 1) |
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45 | (5) |
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5.6 Trees with repeating branches of the type (1, t, 1) |
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50 | (3) |
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5.7 The trees A, B, ..., T listed in Theorem 5.4 are unitrees |
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53 | (3) |
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5.8 Appendix: the inverse enumeration problem |
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56 | (3) |
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Chapter 6 Computation of Davenport--Zannier pairs for unitrees |
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59 | (28) |
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6.1 Reciprocal polynomials |
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59 | (1) |
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6.2 Remarks about computation |
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60 | (1) |
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6.3 Stars and binomial series |
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61 | (1) |
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6.4 Forks and Hall's conjecture |
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62 | (2) |
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64 | (8) |
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6.6 Series F and G: trees of diameter 4 |
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72 | (5) |
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6.7 Series H and J: decomposable ordinary trees |
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77 | (3) |
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80 | (2) |
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82 | (5) |
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Chapter 7 Primitive monodromy groups of weighted trees |
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87 | (12) |
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7.1 Monodromy group of a dessin |
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87 | (2) |
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7.2 Primitive and imprimitive groups |
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89 | (2) |
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7.3 A menagerie of groups |
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91 | (1) |
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7.4 Primitive groups containing a cycle: Gareth Jones's classification |
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92 | (2) |
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7.5 Main theorem: statement and commentaries |
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94 | (1) |
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95 | (4) |
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Chapter 8 Trees with primitive monodromy groups |
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99 | (38) |
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Chapter 9 A zoo of examples and constructions |
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137 | (18) |
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137 | (3) |
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9.2 Difference of powers over Q: infinite series |
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140 | (1) |
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9.3 Polynomials with a relaxed minimum degree condition |
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141 | (2) |
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9.4 Duality and self-duality |
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143 | (3) |
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9.5 A "historic" sporadic example |
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146 | (2) |
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9.6 Some sporadic examples of Beukers and Stewart |
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148 | (4) |
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9.7 Sporadic examples of "megamap invariant" |
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152 | (2) |
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9.8 One more application due to David Roberts |
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154 | (1) |
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Chapter 10 Diophantine invariants |
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155 | (8) |
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10.1 Pell's equation: preliminaries |
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155 | (3) |
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10.2 When a quadratic orbit splits into two rational ones |
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158 | (2) |
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10.3 When the discriminant is a perfect square |
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160 | (1) |
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160 | (3) |
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163 | (12) |
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11.1 Enumeration according to the weight and the number of edges |
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163 | (2) |
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11.2 Dyck words and weighted Dyck words |
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165 | (2) |
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11.3 Proof of the three enumerative theorems |
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167 | (2) |
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11.4 Enumeration according to a passport |
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169 | (6) |
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Chapter 12 What remains to be done |
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175 | (4) |
Bibliography |
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179 | (6) |
Index |
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185 | |