Mathematics 312, Introduction to number theory, Section 101,
Fall 2015, MWF 1111:50, Leonard S. Klinck (LSK) Building.

Instructor :
Zinovy Reichstein
Office: 1105 Math Annex
Office hours: Tu 34:30, We 34:40
Phone: 8223929
Email: reichst at math.ubc.ca
Textbook :
K. Rosen, Elementary Number Theory,
6th edition.
Course syllabus :
This course is intended as an introduction to the basic
concepts of number theory, such as prime numbers, factorization,
and congruences, as well as some of their applications,
particularly to cryptography. Proofs are integral
to the subject, they will be given in class and problems
involving proofs will appear on the homework
and on the tests. Regular reading and working through problems
from the text are an essential part of the course.
Wednesday, September 9. Lecture 1. A brief history of number theory.
The wellordering principle and mathematical induction.
Slides from Lecture 1.
Friday, September 11. Lecture 2.
Strong mathematical induction (section 1.3).
Divisibility (section 1.5).
Slides from Lecture 2.
Monday, September 14. Lecture 3.
Divisibility (section 1.5), prime numbers (section 3.1),
greatest common divisor (section 3.3).
Notes from Lecture 3
by
Prof. Vatsal
Wednesday, September 16. Lecture 4.
Greatest common divisor (section 3.3), the Euclidean algorithm
(section 3.4)
Slides from Lecture 4
Friday, September 18. Lecture 5.
The Euclidean algorithm (section 3.4), fundamental theorem of arithmetic
(section 3.5).
Slides from Lecture 5
Monday, September 21. Lecture 6.
Linear diophantian equations (section 3.7).
Slides from Lecture 6
Wednesday, September 23. Lecture 7.
Conguences (section 4.1).
Notes from Lecture 7
by
Prof. Vatsal
Friday, September 25. Lecture 8.
"Unfinished business" on linear diophantian equations (section 3.7),
congruences (section 4.1).
Notes from Lecture 8
Monday, September 28. Lecture 9.
Representation of integers (section 2.1),
repeated squaring (section 4.1).
Notes from Lecture 9
Wednesday, September 30. Lecture 10.
Linear congruences (section 4.2).
Notes from Lecture 10
Friday, October 2. Lecture 11.
Inverses mod m (section 4.2), Chinese remainder theorem (section 4.3).
Notes from Lecture 11
Homework :
Homework assignments
will be collected in class on Fridays, usually
on a weekly schedule. Homework problems will ask
students to apply theorems from class to carry
out calculations, and also to write their own proofs.
While homework assignments only count for a fairly small
percentage of the total course mark, they are, arguably
the most important part of the course. You need to do them
in a regular basis to practice, absorb and internalize
the material in a way that cannot be replicated by just
listening to the lectures or lastminute cramming for exams.
Please allow yourself plenty of time to carefully
work through each homework assignment, and don't get behind!
A portion of each assignment
will be graded by the course marker. Late homework
will not be accepted. Students are allowed
to consult one another concerning the homework problems.
However, your submitted solutions must be written by you
in your own words.
Homework problems and solutions
Tips for writing solutions to mathematics problems
Evaluation : Course marks will be based on
the homework (10%), two midterms (20% each) and the final exam (50%).
The midterms will be given in class during regularly scheduled
class hours, Wednesday, October 14 and Monday, November 16.
The final exam schedule for December 2015
will be announced later in the term.
Please make sure you do not make travel plans, work plans,
etc., without regard to the examination schedule in this class.
Calculators can be used to solve homework problems.
No calculators, books or notes will not be allowed on the exams.
Missed exam policy :
There will be no makeup or alternate exams in this class.
If you miss a midterm, your score will be
recorded as 0, unless you have a serious documented
reason (an illness, a death in the family, etc.), in which case you
should discuss your circumstances with me as soon as possible.
Missed finals are not handled by me or the Mathematics
Department. Students with legitimate reasons
for missing the final exam should request
a ``Standing Deferred" status through their faculty.
Sections in the book to be covered.
Some changes during the term are possible.
1. The Integers
1.3 Mathematical induction 1.3
1.5 Divisibility 1.5
2. Integers representations and operations
2.1 Representations of integers.
3 Primes and Greatest Common Divisors
3.1 Prime numbers
3.2 The distribution of primes
3.3 Greatest common divisors
3.4 The Euclidean algorithm
3.5 The fundamental theorem of arithmetic
3.7 Linear Diophantine equations
4 Congruences.
4.1 Introduction to congruences
4.2 Linear congruences
4.3 The Chinese Remainder Theorem
5 Applications of Congruences
5.1 Divisibility tests
5.2 The perpetual calendar (will not be covered on final exam)
5.5. Check digits (ISBN code only)
6 Some Special Congruences
6.1 Wilson's Theorem and Fermat's Little Theorem
6.2 Pseudoprimes
6.3 Euler's Theorem
7 Multiplicative Functions
7.1 The Euler phifunction
7.2 The sum and number of divisors
7.3 Perfect numbers and Mersenne primes
8 Cryptology.
8.1 Character ciphers
8.4 Public key cryptography
8.6 Cryptographic protocols and applications (digital signatures only)
If time permits, additional topics from Chapters 9, 10 or 11.