homework 2 updated

The statement of question 4(a) is modified for clarification.

supplementary exercises 2

The supplementary exercises for homework 2 are posted.

lecture 12-13

We have introduced some very basic set theory and some simple counting techniques. Next week will be more interesting.

solutions for homework 1 and supplementary exercises

Solutions for homework 1 and supplementary exercises are posted. (The hard problems in the supplementary exercises are just for fun and no solutions are provided.) No late submissions are accepted now. Please start to review the material for midterm as soon as possible. If you have any questions please come to ask me during my office hours (today 10am-5pm).

homework 2

Homework is posted and the due date is on Oct 30 (5pm sharp). You are advised to start early. Please comment if you have any questions.

midterm

Midterm will be on Nov 2 (in class).

lecture 10-11

We have covered the Chinese remainder theorem and the applications of number theory to cryptography. It illustrates how (not-so-difficult) mathematics can be very useful in computer science. These are the more interesting but more difficult part of this topic. Feel free to comment if you have any questions.

homework 1

Homework 1 and the supplementary exercises are posted. Please feel free to ask questions.

lecture 9-10

We have covered some basic number theory, from greatest common divisor to modular arithmetic to Fermat's little theorem and Wilson's theorem. Note that number theory is a topic that was not covered in high school mathematics, and so everyone has the same background. It is quite fascinating that we have derived some profound statements just from the basic concepts such as greatest common divisor. Please free feel to leave comments if you have any questions about this topic.