Math 4050-A Algebra and Number Theory
Spring 2007

Prof. Monica VanDieren
Dept of Mathematics
Office: John Jay 318
Email: mylastname at rmu dot edu
URL: http://academics.rmu.edu/~vandieren/index.htm
Office hours: other times not listed below by appointment
Mondays 3-4
Wednesdays 11-12, 3-4
Fridays 11-12 and 1-2

Course Description: The spring semester course will cover topics in number theory and abstract algebra as well as set theory and metric space theory. The main goals are to understand the foundations and structure of the real line and to gain fluency with abstract mathematical concepts and proof techniques. The course will also provide the student with an introduction to basic set theory which was invented by Cantor in order to understand the relationship between different infinite sets. His work was motivated by questions surrounding the Fourier series.

Cantor defined the notion of different sizes of infinity. He showed, by a method called diaganolization, that the size of the set of the real numbers is strictly larger than the size of the set of the natural numbers. His work led to the question of whether the continuum hypothesis is true. Roughly speaking, the continuum hypothesis says that there are no sizes of infinity strictly between the size of the real numbers and the size of the natural numbers. Paul Cohen in the 1960s developed a new technique so that he could prove that there was no way to prove the continuum hypothesis was true (or false) within the rules and axioms that mathematicians use.

Topics to be covered include basic properties of natural numbers, countable and uncountable sets, construction of the real numbers, some basic facts about the topology of the real line, cardinal numbers and cardinal arithmetic, the continuum hypothesis, well ordered sets, ordinal numbers and transfinite induction, the axiom of choice and Zorn's lemma. Topics covered in number theory include mathematical induction, divisibility algorithms, factorization methods, primes, congruences, and Diophantine equations. Topics covered in abstract algebra include binary and equivalence relations, groups and subgroups, isomorphisms and homorphisms, rings, and ideals.


Schedule

(subject to change)

Date Topics Assignments
Preliminaries
Mon, Jan 8 Sets
1.1 Russell's Paradox, Inclusion, Subsets, Power Sets
Reading for Wed Chapter 1 Sections 1 and 2
Homework 1 due Friday, Jan 12: Section 1.1 problems 2, 3, 6, 7 and 8.
Wed, Jan 10 Set Operations
1.2 Intersection, Union, Complementation, Symmetric Difference, Subtraction, DeMorgan's Laws.
Reading for Fri Chapter 1 Section 3
Homework 2 due Friday, Jan 19: Section 1.2 problems 5, 7ad, 8b, 9a, 10
and Section 1.3 problems 2, 4, 5, 8, 10
Suggested problems (not to be turned in): Section 1.2 problems 3, 4, 7bc, 8a
Fri, Jan 12 Partially Ordered Sets
1.3 Posets, density, least upper bounds and greatest lower bounds.
Reading for Mon Chapter 1 Section 4.
Suggested problems (not to be turned in): Section 1.3 problems 6, 7
Mon, Jan 15 More on Posets
1.3 Chains, lattices, distributive and complete lattices, Boolean Algebras.
 
Wed, Jan 17 Functions
1.4 Functions, one-to-one, onto, composition.
 
Fri, Jan 19 More on Functions
Inverse, image and pre-image of sets, order isomorphisms.
A natural partial ordering on functions.
Homework 3 due Friday, Jan 26: Section 1.3 problems 14 and 16 and Section 1.4 problems 3, 6, 7, 9b, 10ab, 14
Suggested problems (not to be turned in): Section 1.4 problems 1, 2, 4, 5, 9acd, 10cd, 12
Mon, Jan 22 More on functions.
Every countable chain of functions has a least upper bound.
 
Wed, Jan 24 More on functions and isomorphisms
Every poset L which has maximum chain length n, can be decomposed into n totally unordered subsets.
 
Fri, Jan 24 Countable and uncountable sets
 
Mon, Jan 29 Uniqueness of countable dense linear orders without endpoints.
 
Wed, Jan 31 Uniqueness of countable dense linear orders without endpoints.
 
Fri, Feb 2 Uniqueness of countable dense linear orders without endpoints.
Go over homeworks.
Homework 4 due Friday, February 9: Section 2.1 problems 7 and 8
Groups
Mon, Feb 5 Groups
Some definitions and examples including symmetric groups.
 
Wed, Feb 7 Permutation and symmetric groups.
 
Fri, Feb 9 More symmetric groups
Groups of symmetries of the square, subgroup, Cayley tables, commutative groups.
 
Mon, Feb 12 More on symmetric groups
Groups of symmetries on the cube, rotations of the octogon.
Definition of order of a group and group isomorphism.
 
Wed, Feb 14 Weather related school closure
 
Fri, Feb 16 Subgroups
Subgroup generated by a set.
 
Mon, Feb 19 Division Algorithm
Homework 5 due today.
Wed, Feb 21 Euclid's Algorithm for finding GCDs
 
Fri, Feb 23 Statement of Fundamental Theorem of Arithmetic.
Proof of Euclid's Lemma, sqrt(2) is not rational and there are infinitely many primes.

 
Mon, Feb 26 Fundamental Theorem of Arithmetic and Mathematical Induction
Homework 6 is due today.
Wed, Feb 28 Mathematical Induction
 
Fri, Mar 2 Mathematical Induction
Tower of Hanoi lab
 
Mar 5-9 Spring Break
 
Mon, Mar 12 Equivalance relations
  • definition
  • partition proposition
  • examples
  • search algorithm: hashing
Homework 7 is due today.
Wed, Mar 14 More examples of equivalence relations and groups
(Z_n, +) and (Z_p-0, *)
 
Fri, Mar 16 More on the groups (Z_n, +) and (Z_p-0, *)
 
Mon, Mar 19 Review for the exam
Homework 8 is due today.
Wed, Mar 21 Midterm exam
 
Finite Group Theory
Fri, Mar 23 Chinese Remainder Theorem
 
Mon, Mar 26 Applications of the CRT and definition and examples of cosets
 
Wed, Mar 28 Lagrange's Theorem
 
Fri, Mar 30 Corollaries of Lagrange's Theorem
And, there is no subgroup of A_4 of order 6.
 
Mon, April 2 Index of the stabilizer is the size of the orbit
 
Wed, April 4 Burnside's Lemma
Homework 9 is due.
Fri, April 6 No class
 
Mon, April 9 Applications of Burnside's Lemma
 
Wed, April 11 More applications and review for exam
Homework 10 is due.
Fri, April 13 Midterm Exam
 


Last modified: April 2 2007