CS 381 Homework 9

Hand in the following questions:

1. Textbook p. 479
     1 b, c, e
     2 a
   

2. Recursively define the relation {< a, b > | 3a = b }, where a and b are natural numbers.
   
3. List all binary relations on { 1, 2 }.
   
4. A unary relation is a set of 1-tuples. Prove that there are 2ⁿ unary relations on a set of cardinality n .

Due July 31, 2006 end of the day

You may discuss these questions among yourselves and/or with me. But you must write the answers in your own words.