Last updated: April 27, 2014.

Welcome to the Math 3040 web page (pi.math.cornell.edu/~web3040/). This page contains information about: course organization, homework, and contacting the instructor or TA, as well as important announcements. The information will be updated throughout the term, so please consult this page and the homework assignments regularly to make sure you have the most recent version.

R. Connelly's office hours: 1:30-2:15 Wednesdays in Malott 433.

Z. Tu's office office hours: 2:00-4:00 Fridays (Feb. 6- March 20).

Announcements: The midterm Prelim will be held on February 27, 2014 during class time. Note the change in day.

The final examination for the course will be held on TBA.

What follows is the intended course syllabus for the first few
weeks. A syllabus for the remaining weeks will be adjoined to this
later in the term.

Text: Martin V. Day: *An Introduction to Proofs and the Mathematical Vernacular*

Please turn in your homework in a printed legible format. The following are the reading assignements for the week indicated. Please read the indicated sections before you come to class so we can have an informed discussion in class.

Some people who are asked and who have volunteered will present a "proof" verbally in class, and it will be subject to the scrutiny of their classmates. For those people, this can be in place of a homework assignment or take-home prelim.

Please hand in your homework as a typeset document in LaTeX.

Quizzes, Prelims and Final: There will be:

1) a few unannounced quizzes throughout the term, usually of 10-15 minutes duration;

2) two in-class prelims, the first on Thursday, February 20, 2014 in class,

3) a final exam on TBA

Grading policy: The following is roughly how the different components of your work will be weighted to determine your final grade: Homework, 15-20%; Classwork (including class participation and quizzes), 20-25%; Prelims, 15% each; Final exam, 30%. The Mathematics Department's (voluntary) guidelines for the mean grade in courses at this level is B+. We expect that this will be close to the mean for this course.

Academic Integrity: The usual rules for academic integrity will apply to all work submitted for credit in this course. Of course, this includes prelims and the final exam. You may consult with other students about the homework exercises---in fact, this can be a helpful way of learning the material---but the homework you submit should show all your work and be in your own words. Also be very careful about quoting sources that you use, whether it is from your roommate, the web, the bible, or your mother. Failure to do so could be a basis for plagiarism.

Writing homework in TeX: I strongly suggest that you write your homework in the language of LaTeX. You can download the software TeXShop or MiKTeX for Windows for free. You should follow the instructions for downloading, installing and running the software. Good luck. Here is a nice simple template, from Professor Tara Holm, that Louisa Schwartz suggested that could be used to get started.

Possible project subjects:

- Euclidean geometry: Dissections, Scissors congruence, tensegrities, convexity, polyhedra, Platonic solids, Archemedean semiregular solids, what is a fair die?, tilings.

- Set theory and logic: The lambda calculus, Dedekind cuts, Godel's Theorem, etc.
- Analysis: Proof of the intermediate Value Theorem, Proof of the mean value theorem, etc.
- Linear Algebra: one-to-one linear functions from a finite-dimensional space to itself are onto, the spectral theorem, etc.

- Topology: Knot theory, classification of 2-manifolds, Hairy ball theorem, Brouwer's fixed point theorem.

- Number theory: Fermat's Last Theorem, Fermat's Little Theorem and cryptography.
- Probability: Bayes' theorem, Monty Hall problem.
- Collatz conjecture.
- A flexible polyhedral surface.

Problems: 1.3, 1.6, 1.8. Read Quinn's article,
Quinn-Jaffe article, and Bill Thurston's reply. On Tuesday be prepared to answer the
question: "Is there a place in mathematics for physical
intuition?". Whatever you think, make your arguments clearly and
logically.

Due Thursday, January 30, 2014 in class.

Here is a Proof of the Cauchy-Schwarz inequality that we discussed in class. This is the basic TeX.

**Week 2: ** Valid arguments, Quantifiers, and Proofs. Sections D, E, F.

Problems: 1.19, 1.20, 1.24, 1.29, 1.31. Equivalence Relations.

**Week 3**: Read Chapter 2A.

Problems: 2.1, 2.4, 2.5, 2.7, 2.8, 2.10

Due Thursday, February 13, 2014 in class. Solutions

**Week 4**: Read Chapter 2B. Induction and Proof techniques.

Problems: 2.12, 2.14, 2.18, 2.20, Problems on Pythagorean triples.

Due Thursday, February 20, 2014 in class. Solutions

**Week 5**: Read Chapter 3A, 3B, 3C. Sets and functions.

Midterm Prelim: In class covering Chapters 1 and 2. February 27, 2014 during class time. Note the change in day.

Practice problems and reminder of subjects covered on the Prelim.

A second chance for Prelim 1.
You can hand in solutions to the problems you did not get during the
exam period. Please LateX your solutions and have them in
by Tuesday, March 11. Here is the exam.

**Week 6**: Continue to read Chapter 3A, 3B, 3C, 3D, 3F. Sets and functions.

Problems: 3.1, 3.5, 3.12, 3.15, 3.16. Due Thursday, March 6, 2014, in class. Solutions

**Week 7**: Continue to read Chapter 3D, 3F, 3G. Sets and functions.

**Week 8**: Read Chapter 1 of Introduction to Probability, by Grinstead and Snell.

Solutions

Problems: Problems 15 and 16 page 73 of Grinstead and Snell's text. Problems 4.16, 4.17 and 4.24 in Day's text. Due Thursday, March 27, 2014, in class. Solutions

**Week 10**: Continue to read Chapter 4 of Day's Text:

Problems: 4.15, 4.20, 4.25, page 88, in Day's Text. Number Theory problems. Due Thursday, April 17, 2014, in class. (We will have presentations on Thursday.) Note the later due date for these problems and corrections to the Number theory problems, especially Problems 1 and 2.

**Week 11**: Projective Geometry. Please read the following and hand in the problems on Thursday, April 24, 2014. Solutions.

Take Home Prelim, due April 29 in class. The rest of the time will be taken up with presentations.

**Week 12**: Presentations on any subject. (Suggestions above.)