1323 CSCI (Discrete Structures), Spring 2001 Homework 4
Assigned: January 30, 2001. Due: February 6, 2001, at the start of class. Credit: 20 points.
1
Problems
1. (4 points) Using the predicate symbols shown and appropriate quantiers, write each Englishlanguage statement as a predicate w. (The domain is the whole world.) W (x) is x is a positive integer. P (x) is x is prime. G(x, y) is x >= y. Some positive integers are prime.
Not all positive integers are prime.
For every positive integer n, there is another positive integer such m that m is prime and m >= n.
There is a largest prime. 2. (5 points) 3. (5 points) Do problem 12 on p. 57 of the textbook. Do problem 16 on p. 57 of the textbook.
4. (6 points) Verify the correctness of the following program segment to compute z = |x + y|, the absolute value of x + y. (Hints: You must rst wr...