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## Group TheoryGroup theory is the study of symmetry. Objects in nature (math, physics, chemistry, etc.) have beautiful symmetries and group theory is the algebraic language we use to unlock that beauty. Group theory is the gateway to abstract algebra which is what tells us (among many other things) that you can't trisect an angle, that there are finitely many regular polyhedra, and that there is no closed form for solving a quintic. In this class we will get a glimpse of the mathematics underlying these famous questions. This course will focus specifically on building groups from other groups, exploring groups as symmetries of other objects, and using the tools of group theory to construct fields. |
18 weeks ## DiagnosticsARE YOU READY? |

18 weeks ARE YOU READY? |

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There are no classes on September 7, November 23-27, or December 19-January 3.

### Who Should Take?

This class is aimed primarily at students who have mastered the standard high school curriculum and do not have access to a strong post-secondary curriculum. We assume fluency with modular arithmetic, the complex numbers, and basic combinatorics, and also a good background in forming mathematical arguments and writing proofs. The class will be on the level of the most difficult Art of Problem Solving courses. We will not assume any calculus, but we will rely on precalculus, number theory, and counting extensively.### Lessons

Lesson 1 | Symmetry |

Lesson 2 | Examples of Groups |

Lesson 3 | Cyclic Groups |

Lesson 4 | Abelian Groups |

Lesson 5 | Group Actions I |

Lesson 6 | Group Actions II |

Lesson 7 | Quotients |

Lesson 8 | Functions from Groups to Groups |

Lesson 9 | Group Presentations |

Lesson 10 | Symmetric and Alternating Groups |

Lesson 11 | Group Classification and Sylow's Theorems |

Lesson 12 | Examples of Fields |

Lesson 13 | Building Finite Fields |

Lesson 14 | Polynomials |

Lesson 15 | Vector Spaces and Dimension |

Lesson 16 | Number Fields and Constructions |

Lesson 17 | Galois Groups of Finite Fields |

Lesson 18 | Automorphisms of Number Fields and Solving Quintics |