Fall 2007

MATH 4361 – Modern Algebra

 

Date

Section

Assignment

Aug 15

The Well-Ordering Principle and the Principle of Mathematical Induction.

Read Section 1.1. Pay special attention to examples.

Suggested problems: Section 1.1: 1-6; 10, 11, 12(those of you who took Real Analysis must have seen this problem before).

Class handout: 1, 2, 4.

Aug 20

Relations. Equivalence relations. Classes of equivalence.

Hw#1: from handout given on Aug. 15: 1(d, f), 2(c).

           Section 1.2: 7, 8, 11.

Read the pages on Equivalence relations and the examples from the text. Suggested pb: 7, 9. See some additional problems.

Read 1.2 and 1.3.

Aug 22

Arithmetic and divisibility.

Gcd and the Euclid’ Algorithm.

Read 1.2 and 1.3. See Hw#1 revised above.

Suggested pb: section 1.3: 1, 2, 3, 4, 5, 6, 7, 8, 9.

See some sample solutions to text problems.

Aug 27

Finding the lcm(a,b); Diophantine equations.

Hw#1 due

Suggested pb: section 1.3: 10, 11. See also from above.

Remember also the question addressed in class: If gcd(a,b)=1 then does the equation ax+by=c, (c integer)  always have solutions in Z? 

Here are some more problems for you.

Aug 29

Section 1.4. Prime numbers and the Fundamental Theorem of Arithmetic.

Hw#2: Task 1(page 15); page 25: 9, 11; page 31: 2, 4.

Here are some notes on problem 5 section 1.4.

Read section 1.4 and go over the result with paper and pencil trying to understand the proofs.

Look at sections 1.5 and 1.6. Maybe we can have presentations on Fibonacci numbers, and using Euclid’s algorithm to discuss the Golden ratio and continued fractions!

Sept 3

Labor Day. No classes.

Have  great weekend, but don’t forget Modern Algebra!

Sept 5

Theorems of Euler and Fermat (section 1.7)

Selected solutions to problems from Hw#1 are now posted.

Hw#2 due

Read section 1.7. Try to understand on your own the proof of Euler’s theorem (Theorem 3).

Suggested problems: section 1.7: 1, 2, 3, 4, 6, 7. If you like a challenge try 9 as well.

Selected solved problems from 1.7

A practice test is posted on the Resources page.

Sept 10

Review for exam

 

Sept 12

Exam 1

 

Sept 17

Modular arithmetic. Congruences.

Read Section 2.1. Read ahead on linear congruences and solving them.

Suggested pb.: section 2.1: 1, 2, 3, 5, 6, 7, 8, 15. Try 9, 11, 12.

Sept 19

Solving linear congruences.

Read section 2.1 again. More pb: 11, 12, 13, 14, 15, 17, 18.

Read 2.2 Worksheet 2: Divisibility tests. I will not be spending time in class with them, but there are some nice and quite elementary results.

Hw#3: section 2.1: 2, 3, 9(ii, iv, v), 11(ii, iii), find  in both mod 9 and mod 15. Section 2.4: 3, 5(ii, v, vi), 12.

Sept 24

The ring of congruences mod m.(section 2.4)

Suggested problems: section 2.4: 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14.

See some solved problems and some suggested ones in the notes.

Sept 26

Rings and Fields (section 2.5)

Hw#3 due

For next class: read 2.5

Suggested problems: 2.5: 1, 2, 3, 4, 5, 6, 7, 8, 11, 12… I would better say all of them, or almost all of them.

Enjoy the weekend! 

  Oct 1

The Field of Complex Numbers.                                                                         

Read 2.6, “to the teacher” notes included. Also, read 2.7 and 2.8

Suggested problems: 2.6: 1, 2, 6, 7, 8, 9.

Have a look at the problems at the end of the chapter, on page 108. Look closer at 18.

More to come…

Oct 3

More on Complex numbers.

Some class notes and problems.

Oct 5

Review in CL 2003 from 1:30-3:00 pm

 

Oct 8

Review

Additional problems on 2.6:10, 11, 12, 13, 14, 17.

Page 109: 3, 4, 5, 10, 11, 12, 16, 18, 19, 20, 22.

Oct 10

Exam on Chapter 2

Hw #4: problems 1, 2 in the class notes above, pb. 22 page 109 (text).

Read ahead Chapter 3: 3.1 and 3.2. They are not difficult.

Have a great weekend!

Oct 15

Polynomial arithmetic: Chapter 3

Read 3.1.

Hw#4 due postponed until Wednesday

Added to hw4: section 3.1: 3(ii),5(iii), 10.

Suggested problems: work as many as you can.

Oct 17

Check the Employer showcase. It is today right under your nose (i.e in Science Atrium and Clendenin lobby)!

Hw#4 due

 

Oct 22

Some problems on factoring polynomials.

Derivatives of polynomials: 3.3

Read 3.3.

Suggested problems: section 3.2: 3, 4, 5, 6, 7(you may use the method we used in class or the quadratic formula)

Section 3.3: Tasks on page 130: 1, 2, 3.

Hw#5: prove Proposition A page 129, Task 2 on page 130;

         section 3.2: 4(iii), 5(iii do it also in Z_3[x]).

Oct 24

Factoring in Z[x] and Q[x].

Hw#5 continued from above: section 3.4: 5(ii), 7(ii).

Oct 26

I will be in CL 1005 between 9-11 and in my office after that if anybody needs me!

 

Oct 29

The Fundamental Theorem of Algebra. Polynomial congruences (section 3.7).

Hw#5 due

Read section 3.5. pages 136-142. You may skip the proof of the theorem. Read section 3.7: pages 150-154.

Suggested problems: Section 3.5: 1, 2, 4, 6, 7, 8(try it). Page 146: 1, 2, 3, 6.

Section 3.7: 1, 2, 3, 4.

Oct 31

Polynomial congruences.

Suggested problems: section 3.7: 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17.

Nov 5

Review for Exam 3

Look at the Resources page for new links to texts and study guides for modern algebra and some interesting articles.

Some extra problems to keep you company over the weekend!

Nov 7

Exam #3: Chapter 3 what was covered in class

Solutions to selected problems from the list of practice problems from above.

Nov 12

Introduction to groups.(section 4.1)

Read section 4.1.

Suggested problems: 1, 2, 3, 4, 5, 6, 7, 8, 9-19 (they are all interesting).

Nov 14

More on groups (still 4.1)

Read carefully the examples in 4.1.

Read sections 4.2 and 4.3. They are very interesting!

Hw#6L (the last hw of the semesterJ): ex. 6, 16, 33, 49 class handout;

Here are some solved problems on groups.

Nov 19

Subgroups.(section 4.4) Cyclic subgroups.

Hw#6 is due by Tuesday, Nov 20, 3pm.

Suggested problems: All in section 4.4 are great problems. Enjoy them!

Some solved problems on section 4.4

Nov 26

 

 

Nov 28

Exam #4: Chapter 4, sections 4.1 and 4.4

 

Dec 3

Last day of classesJ, but I am going to miss youL guys.

If you decide you don’t need to take the final I wish you Happy Holidays, have a wonderful end of semester and year and best of luck in the future!

If you are taking the final, let me know if you want to do a review session this week.

Since not all of you came to me to see the grades I will post them on WebCT. The final exam is not going to lower the grade, I want to offer a chance to you to get a better grade or a passing grade even if your average may seem quite low at this moment.

I will be here this week, but I will try to offer a review on Friday, around 1:30 if I know there will be more of you coming. If I hear from you I will try to set the day and time to accommodate more.

Dec 7

Review in CL 2003 1:30-3Pm