Mathematics Department | Illinois State University

Math 236, Section 1, Elementary Abstract Algebra

Professor: George Seelinger
Office: Stevenson 313C (Enter through STV 313)
Phone: 438-8781
Office Hours: W 2:00-2:50, R 11:00-11:50, F 12:00-12:50

TEXT: Abstract Algebra, An Introduction, by Thomas W. Hungerford, 2nd Edition, Brooks/Cole, 1997.

Here you will find links to the current assignments, possible posting of hints, and other resources available on the WEB.

Some Definitions and Theorems (To be updated throughout the semester.)

ABOUT THE COURSE: In this course we will cover most of Chapters 1-6 and Chapter 12 of the text with occassional excursions in the appendices. We will start by examining the familiar set of integers. Our emphasis in looking at the integers is twofold. First, we want to emphasize the algebraic properties of the integers. Second, we want to try to develop the students' ability to understand theoretical mathematical arguments and to be able to write coherent mathematical arguments. Almost all of the mathematical arguments you will be expected to understand and to write take the form of mathematical proofs. Once we gain some experience in the relatively concrete setting of the integers, we will develop some understanding of abstract rings and the functions between them. In this less familiar context, the skills of mathematical argumentation that we developed earlier will become more important to the understanding of these topics. To further our understanding of rings, we then look at the arithmetic of polynomials as an example of a ring that is not the integers. We will then begin the study of quotient fields and the construction of field extensions, the depth of this coverage will depend on the time available at the end of the course.

GRADING: In this course you will be graded on your performance on three one hour in class exams, a comprehensive final exam, and weekly homework assignments. The relative weights of these components will be

   Test 1       100 pts  (Friday, Feb. 17) 
   Test 2       100 pts  (Friday, Mar. 23) 
   Test 3       100 pts  (Friday, Apr. 27) 
   Homework     150 pts
   Classwork     50 pts 
   Final Exam   200 pts  (Tuesday, May 8, 3:10 - 5:50 pm, STV 229)  

Exam I Solutions
Exam II Solutions
Exam III Solutions
Final Exam Review Problems

HOMEWORK: Homework assignments will consist of four or five proofs a week. Assignments will be given in class and will be due each Thursday by the beginning of class. As developing your skills at writing mathematical arguments is one of the central goals in this course, doing as much as you can on each homework assignment is essential for a good grade. NOTE: In general you should not expect to be able to do a good job on a homework assignment if you start the day before it is due. Some problems may require numerous attempts before you will be able to solve them. As well as the formal written assignments given in class, it will be necessary for most students to read and re-read the relevant sections of the text. For your FIRST READING ASSIGNMENT please read ``Appendix A, Logic and Proof'' (pp. 493-503) in the text.

Homework Assignments:

Homework #1, due Jan 26: Sect 1.1, p.6-7 # 5, 6, 8; Sect 1.2, p.13 # 4, 8.
(See proof-writing tips to help with doing your homework.)
Homework #2, due Feb 2: Sect 1.2, p. 13-14 # 15, 28, 33; Sect 1.3, p.18-19 # 8, 16.
(HINT: Sect 1.2, # 28: Write d in the form au+bv and consider cd.)
Homework #3, due Feb 9: Sect 1.4, p. 23 # 10, 13; App D, p. 531 # 16; Sect 2.1, p. 29-30 # 15, 23
Homework #4, due Feb 16: Sect 2.2 # 7, 8; Sect 2.3 # 4, 7, 8
Homework #5, due Feb 23. (See the pdf file for this assignment by clicking here.)
Homework #6, due Mar 1: Sect 3.1 # 5, 9, 18, 22 (Note that for Problem 22, it might be useful to review the properties of logarithms. A review sheet can be found here.)
Homework #7, due Mar 8: Sect 3.2 # 5, 11, 12, 14, 22
Homework #8, due Mar 22: Appendix B # 27, 35; Sect 3.3 # 10, 19, 25
Homework #9, due Mar 29: Sect 3.3 # 28, 31; Sect 4.1 # 5, 12
Homework #10, due April 6: Sect 4.2 #6, 14, 15
Homework #11, due April 12: Sect 4.3 #9, 12, 14, 21
Homework #12, due April 19: Sect 4.4 #8, 19, 24; Sect 4.5 #5, 6
Homework #13, due April 26: Sect 4.5 #18; Sect 5.1 #10, 12; Sect 5.2 #2, 7
Homework #14, due May 4: Sect 5.3 # 1, 5, 8, 9 | Solutions


Worksheet 1: Euclidean Algorithm (Due Friday, Jan 27).
Worksheet 2: Arithmetic of Remainders (Due Thursday, Feb 9).
Extra Credit Worksheet: Ring Isomorphsisms.
Worksheet 3: Irreducibility in Q[x] (Due Friday, April 20).
Worksheet 4: Field Extensions and Factoring (Due Thursday, May 3) | Worksheet Solutions

Other Files/Handouts:
Some Addition and Multiplication Tables for Zn
Solving Some Congruences in Zn
RSA Encryption Example using Sage
Statement and Proof of Lemma 3.3
The Quaternion Example from Feb 29th
Example of Euclidean Algorithm in Z5

Algebra on the WEB:
Sage Math Online
The Development of Ring Theory (Article by: J J O'Connor and E F Robertson)
First 1000 Primes
The Great Internet Mersenne Prime Search Project (GIMPS)
The Millennium Problems posed by the Clay Mathematics Institute.