Homework 6

For the weeks of Oct. 5-9 and Oct. 12-16.
  1. Do Exercise 4.12.
  2. Do Exercise 4.25. For each part, say whether or not the formula defines a surjections, then justify you answer by proving that it does or does not, as the case may be.
  3. Do Exercise 4.31. Hint: Prove by contradiction.
  4. Do Exercise 4.37.
  5. Do Exercise 4.48.