1. 9.1.2

2. 9.1.12

3. 9.2.4

4. 9.2.10

5. 9.3.4

6. 9.3.14

7. 9.4.2a,b

8. 9.4.10a 9.

9.4.16

10. (extra credit)

Consider all unordered (distinct) pairs of positive integers. Call this set S. Now color the elements of S in any way imaginable using two colors, say red and blue. Prove that either there is an infinite subset of integers, all of whose two element subsets are red, or there is an infinite subset of integers all of whose two element subsets are blue.

Due: Tuesday, May 12, at beginning of class. All work due at that time.

-- RobbieMoll - 03 May 2009