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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
Cosets and Lagrange's Theorem
Left and Right Cosets
Definition of Left Coset
Definition of Right Coset
Coset Representatives
Properties of Cosets
Partitioning the Group
Equal Size of Cosets
Coset Equality Conditions
Index of a Subgroup
Definition and Calculation
Finite and Infinite Index
Lagrange's Theorem
Statement and Proof
Geometric Interpretation
Corollaries of Lagrange's Theorem
Order of an Element Divides Order of the Group
Groups of Prime Order are Cyclic
Subgroups of Prime Index
Fermat's Little Theorem
Euler's Theorem
Applications of Lagrange's Theorem
Counting Arguments
Non-existence Results
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7. Permutation Groups
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9. Normal Subgroups and Quotient Groups