To the homepage of Valentina Kirichenko

Welcome to the Introductory Algebra homepage!

Jacobs University Bremen, Fall 2008

Course number: 100321


Announcement: The final exam will be held in East Hall Room 4 on Friday, December 19, from 13:00 to 15:00
Solutions to the second midterm and practice problems for the final exam are posted.
Final exam will cover everything we have studied (see week by week detais for the exact list of topics).

Impossible square Classes: Mo 11:15-12:30 am, Th 8:15-9:30 am
East Hall 4
Instructor: Valentina Kirichenko
Office: Research I Room 125
phone: 0421-200-3184
e-mail: v.kiritchenko at jacobs-university dot de

Office Hours: Mo 9:15-10:30am, Th 10:45-12:00am and by appointment
Jacobs university logo Teaching Assistant: Todor Milev
Office: Research I Room 129A
phone: 0421-200-3582
e-mail: t.milev at jacobs-university dot de

Office Hours: Tu,Th 5-6pm


Textbook: A First Course in Abstract Algebra, John Fraleigh

There are three copies available in the library on reserve.

You might also find helpful the following notes for this course by Michael Stoll.
Another good source is "Algebra" by Michael Artin. There are some copies in the library and I have my own copy which you can borrow.


Sillabus: Algebraic structures can be found everywhere in mathematics; it is therefore important to become familiar with them. This course gives an introduction to three basic types of structures: groups, commutative rings, and modules. Here is a more detailed list of topics to be covered.

Group theory: Definitions and key examples. Cosets and Lagrange's theorem. Group morphisms and basic constructions including quotient groups, direct and semi-direct products and exact sequences. Group actions and orbit-stabilizer theorem. Sylow theorems.

Commutative Rings: Definitions and elementary properties. Ideals, ring morphisms and quotient rings. Domains, Euclidean domains, principal ideal domains and unique factorization.

Modules: Definitions and basic constructions. Free modules and torsion-free modules. Structure theory for finitely generated modules over a principal ideal domain.


Grading:   There will be 2 midterm tests, 75 minutes each, given in class. There will also be regular homeworks. Each Thursday a homework assignment will be posted further down on this page. It will be usually due by next Thursday. It is crucial for understanding the course material to do homeworks in a timely fashion. In the end of the course there will be the final exam. The final course grades will be determined as follows:

Homework/Class Participation 40%, Tests 15% each, Final Exam 30%

You can also improve your grade by preparing optional projects. That means either writing a paper and/or doing a presentation in class. You can choose any topic related to this course. Here are some possible topics: insolvability of a general equation of degree >4 in radicals, construction of regular n-gons with compass and straightedge, arithmetics in quadratic integer rings. Please tell me your topic by the end of November and whether you plan to write a paper or do a presentation. The optimal size for a paper is 2-3 pages preferrably typed or writtten very neatly. Keep it short but complete. Mention all sources that you used. All written projects are due by the date of the final exam.
In addition, each homework will contain bonus problems that can give you extra credit. You may submit bonus problems even after the deadline for the rest of the homework.
Week by week details

September 1, 4
Homework 1 due September 11
Set theory, equivalence relations; Complex numbers: polar form, solving equations x^n=a.
Read Sections 0 and 1 in the textbook.
September 8, 11
Homework 2 due September 18
Equivalence classes; Arithmetics modulo n; Unit circle and roots of unity; Binary structures, identity element, inverse element, isomorphism of binary structures; Groups and monoids, subgroups, group homomorphisms.
Review Sections 0 and 1. Read Sections 2, 3, 4 and 5.
September 15, 18
Homework 3 due September 25
Cyclic groups; Direct product of groups; Structure theorem for finitely generated Abelian groups (without proof yet); Free groups, representation of groups by generators and relations, Cayley graphs.
Read Sections 6, 7, 11, 39, 40.
September 22, 25
Homework 4 due October 2
Left and right cosets, Lagrange theorem; Normal subgroups, quotient groups by normal subgroups; Examples with quotient groups of the free Abelian group of rank two; Center of a group.
Read Sections 10, 13, 14, 15
September 29, October 2
Homework 5 due October 9
Homomorphism theorem; Groups of permutations; Cayley theorem; Symmetric groups, cycle decomposition, conjugacy classes.
Review Sections 14,15. Read Sections 8, 9, see also articles in Wikipedia on Partition function and Young diagrams.
October 6, 9
Practice problems
Homework 6 due October 20
Signature of a permutation, alternating group; Groups of symmetries of regular polygons and polyhedra; Solving equations in radicals using symmetric groups, formula for the roots of a cubic polynomial;
Reveiw Sections 8,9. See also articles in Wikipedia on Tetrahedral symmetry, Icosahedral symmetry, Octahedral symmetry, Cubic equation, Quartic equation
October 13, 16
Homework 7 due October 27
Group actions: orbits, stabilizers, Burnside's lemma; Automorphism groups, inner automorphisms of a group. Sylow's theorems and applications.
Read Sections 16,17. See also articles in Wikipedia on Burnside's lemma
October 20, 23
Homework 8 due November 3
Proof of Sylow's theorems; Rings: definitions and examples, rings of integer, rational, real and complex numbers, ring of congruence classes modulo n, ring of matrices.
Read Sections 36, 18. See also an article in Wikipedia on Sylow's theorems
October 27, October 30
Homework 9 due November 10
Division ring of quaternions; Ring homomorphisms: evaluation homomorphisms of rings of polynomials; Characteristic of a ring; Integral domains, field of fractions of an integral domain; Finite fields, multiplicative groups of finite fields; Ideals and quotient rings; Ring homomorphism theorem; Coprime ideals and Chinese Remainder Theorem.
Read Sections 19, 21, 22, 24.
November 3, 6
Principal Ideal Domains, Euclidean domains; Examples: Gaussian integeres, ring of formal power series; Prime and maximal ideals; Prime and irreducible elements; Decomposition into primes and irreducibles; Noetherian rings.
Read Sections 25, 26, 27, 45, 46.
November 10, 13
Homework 10 due November 17
Practice problems
Solutions to the first midterm
Unique Factorization Domains; Quotients by prime and maximal ideals; Ideals in the ring of Gaussian integers and representation of primes by sums of two squares; The ring of polynomials over UFD is a UFD; Euclidean algorithm for Euclidean domains; Classification of finite fields.
Read Sections 45, 47.
November 17, 20
Homework 11 due November 24
Splitting fields of polynomials: existence and uniqueness; Proof of the classification theorem for finite fields; Modules: definitions and examples.
Read Sections 13.6, 12.1 in Artin.
November 24, 27
Homework 12 due December 4
Free modules; Invertible operators on free modules; Hamilton-Cayley Theorem; Structure theorem for finitely generated modules over PIDs; Corollaries: classification of Abelian groups, Jordan Normal Form for linear operators.
Read Sections 12.2, 12.6, 12.7 in Artin
December 1, 4
Practice problems
Solutions to the second midterm
Noetherian modules; Submodules of free modules over PIDs, reciprocal bases; Proof of structure theorem for finitely generated modules over PIDs; Field extensions, degree of a field extension; Impossibilty results for constructions using compass and straightedge (without proof).
Read Sections 12.4, 12.5, 13.1, 13.2, 13.3, 13.4 in Artin