Homework Assignment Twelve

Due: in class on Thursday, May 12 - last day of class (all work due at that time!)

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. 9.4.12
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.

-- RobbieMoll - 03 May 2004