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Mathematics
Group Theory
1. Introduction to Algebraic Structures
2. Definition of a Group
3. Fundamental Examples of Groups
4. Order of Elements and Groups
5. Subgroups
6. Cyclic Groups
7. Permutation Groups
8. Cosets and Lagrange's Theorem
9. Normal Subgroups and Quotient Groups
10. Group Homomorphisms
11. The Isomorphism Theorems
12. Group Actions
13. The Sylow Theorems
14. Direct Products and Sums
15. Structure of Finite Abelian Groups
16. Solvable and Nilpotent Groups
17. Composition Series and Jordan-Hölder Theorem
18. Free Groups and Presentations
19. Semidirect Products
20. Introduction to Representation Theory
21. Applications of Group Theory
Permutation Groups
Definition of a Permutation
Permutations as Bijections
Composition of Permutations
The Symmetric Group
Definition of Sₙ
Structure and Properties
Order of Sₙ
Cycle Notation
Writing Permutations in Cycle Notation
Disjoint Cycles
Definition and Properties
Commutativity of Disjoint Cycles
Products of Cycles
Multiplication of Cycles
Converting between Notations
Cycle Structure
Cycle Type
Order of a Permutation
Calculation from Cycle Decomposition
Least Common Multiple Method
Transpositions
Definition of a Transposition
Every Permutation as a Product of Transpositions
Minimal Transposition Decompositions
Even and Odd Permutations
Definition of Parity
Sign of a Permutation
Properties of Parity
The Alternating Group
Definition of Aₙ
Properties and Structure
Order of Aₙ
Generators of Aₙ
Cayley's Theorem
Statement and Proof
Embedding Groups into Symmetric Groups
Regular Representation
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6. Cyclic Groups
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8. Cosets and Lagrange's Theorem