Math 1090 A Homework 2 Math 1090 A Homework 2
Due October 6 at Noon

  1. Rewrite the following to include ``invisible'' parentheses and test the resulting expression for validity.
    pr    q         r    (p q)  .
  2. Find one state in which the following is satisfied and one state in which it is not satisfied.
    (p q    q r)        (p r).
  3. Fill in the complete details (in the proof style of the ``model proof'') of the proof of (3.42),
    |-  p  p          false  ,
    where the proof steps are given below.
     p
    =
    p     p     pp
    =
    p     p      true
    =
    true     p     p
    =
    true     p     p
    =
    true     false
    =
    false
  4. Using the proof style of the text, prove (3.30):
    |-  p  false         p  .
    You may assume any result with lower number.


File translated from TEX by TTH, version 2.60.
On 18 Sep 2000, 09:09.