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Front Cover |
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Foundations of Galois Theory |
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Copyright Page |
5 |
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Table of Contents |
6 |
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Foreword |
8 |
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Preface |
9 |
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PART I: THE ELEMENTS OF GALOIS THEORY |
12 |
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CHAPTER 1. THE ELEMENTS OF FIELD THEORY |
14 |
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1. Preliminary remarks |
14 |
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2. Some important types of extensions |
15 |
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3. The minimal polynomial. The structure of simple algebraic extensions |
17 |
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4. The algebraic nature of finite extensions |
19 |
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5. The structure of composite algebraic extensions |
20 |
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6. Composite finite extensions |
22 |
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7. The theorem that a composite algebraic extension is simple |
25 |
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8. The field of algebraic numbers |
27 |
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9. The composition of fields |
27 |
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CHAPTER 2. NECESSARY FACTS FROM THE THEORY OF GROUPS |
29 |
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1. The definition of a group |
29 |
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2. Subgroups, normal divisors and factor groups |
31 |
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3. Homomorphic mappings |
34 |
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CHAPTER 3. GALOIS THEORY |
38 |
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1. Normal extensions |
38 |
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2. Automorphisms of fields. The Galois group |
41 |
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3. The order of the Galois group |
44 |
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4. The Galois correspondence |
48 |
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5. A theorem about conjugate elements |
51 |
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6. The Galois group of a normal subfield |
52 |
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7. The Galois group of the composition of two fields |
54 |
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PART II: THE SOLUTION OF EQUATIONS BY RADICALS |
56 |
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CHAPTER 1. ADDITIONAL FACTS FROM THE GENERAL THEORY OF GROUPS |
58 |
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1. A generalization of the homomorphism theorem |
58 |
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2. Normal series |
59 |
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3. Cyclic groups |
62 |
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4. Solvable and Abelian groups |
65 |
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CHAPTER 2. EQUATIONS SOLVABLE BY RADICALS |
71 |
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1. Simple radical extensions |
71 |
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2. Cyclic extensions |
73 |
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3. Radical extensions |
78 |
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4. Normal fields with solvable Galois group |
81 |
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5. Equations solvable by radicals |
84 |
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CHAPTER 3. THE CONSTRUCTION OF EQUATIONS SOLVABLE BY RADICALS |
86 |
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1. The Galois group of an equation as a group of permutations |
86 |
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2. The factorization of permutations into the product of cycles |
88 |
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3. Even permutations. The alternating group |
92 |
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4. The structure of the alternating and symmetric groups |
94 |
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5. An example of an equation with Galois group the symmetric group |
98 |
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6. A discussion of the results obtained |
102 |
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CHAPTER 4. THE UNSOLVABILITY BY RADICALS OF THE GENERAL EQUATION OF DEGREE n ? 5 |
105 |
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1. The field of formal power series |
105 |
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2. The field of fractional power series |
110 |
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3. The Galois group of the general equation of degree n |
114 |
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4. The solution of equations of low degree |
118 |
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