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2021 Faculty Courses School of Science Undergraduate major in Mathematics

Algebra III

Academic unit or major
Undergraduate major in Mathematics
Instructor(s)
Yuichiro Taguchi
Class Format
Lecture
Media-enhanced courses
-
Day of week/Period
(Classrooms)
5-6 Tue (H137) / 5-6 Fri (H137)
Class
-
Course Code
MTH.A331
Number of credits
200
Course offered
2021
Offered quarter
3Q
Syllabus updated
Jul 10, 2025
Language
Japanese

Syllabus

Course overview and goals

The main theme of this course is Galois Theory, based on the theory of finite field extensions, and its various applications. Galois Theory is one of the most important theories in modern algebra, giving foundational approach to modern mathematics, and, at the same time, one can say, one of the final subjects in the undergraduate algebra course.
In this course, we learn the basics of Galois Theory and its applications, including the solvability of algebraic equations and geometrical construction.

Course description and aims

Students are required to learn the basics of the theory of finite field extensions, including the construction of finite extension field via the residue fields, by maximal ideals, of the polynomial ring. After learning the basics including the existence of an algebraic closure of a field, we proceed to Galois Theory, such as the Galois correspondence between subgroups of the Galois group and fixed fields, of which the students are required to have good understanding. Also required is to understand its applications, such as finite fields, the solvability of algebraic equations, and geometrical construction.

Keywords

Galois extension, fundamental theorem of Galois theory, finite field, solvability of algebraic equations

Competencies

  • Specialist skills
  • Intercultural skills
  • Communication skills
  • Critical thinking skills
  • Practical and/or problem-solving skills

Class flow

Standard lecture course accompanied by discussion sessions

Course schedule/Objectives

Course schedule Objectives
Class 1

Fields and their extensions

Details will be provided during each class session

Class 2

Simple extensions, algebraic extensions

Details will be provided during each class session

Class 3

Algebraic closure of a field

Details will be provided during each class session

Class 4

Separable and inseparable extensions

Details will be provided during each class session

Class 5

Isomorphisms of fields, extensions of an isomorphism

Details will be provided during each class session

Class 6

Minimal decomposition fields, normal extensions

Details will be provided during each class session

Class 7

Galois extensions and Galois groups

Details will be provided during each class session

Class 8

Fundamental theorem of Galois Theory

Details will be provided during each class session

Class 9

Calculations of various examples of Galois groups

Details will be provided during each class session

Class 10

Cyclotomic fields

Details will be provided during each class session

Class 11

Trace and norm. Finite fields

Details will be provided during each class session

Class 12

Cyclic Kummer extensions

Details will be provided during each class session

Class 13

Application of Galois Theory: Solvability of algebraic equations

Details will be provided during each class session

Class 14

Application of Galois Theory: Drawing with ruler and compass and examples

Details will be provided during each class session

Study advice (preparation and review)

To enhance effective learning, students are encouraged to spend approximately 100 minutes preparing for class and another 100 minutes reviewing class content afterwards (including assignments) for each class.
They should do so by referring to textbooks and other course material.

Textbook(s)

None required

Reference books, course materials, etc.

E. Artin, "Galois Theory", Dover
N. Bourbaki, "Algebra II", Springer-Verlag
T. Szamuely, "Galois groups and fundamental groups", Cambridge University Press

Evaluation methods and criteria

By exams and reports. Details will be announced in the course.

Related courses

  • MTH.A301 : Algebra I
  • MTH.A302 : Algebra II

Prerequisites

Students are expected to have passed Algebra I and II.