Math 1090 N Homework 3 Math 1090 N Homework 3
Due October 27 at Noon

  1. Prove in the proof style of the text, Transitivity, (3.82)(c),
    |- (p q)    (q r)        (p r).
    You may use any lower numbered theorem in your proof.
  2. Prove the Derived Inference Rule,
    If |- P Q,    |- Q R
    then |- P R
    .
    You may make use of the Derived Inference Rule,
    If |- P
    then |- true P
    and the three basic Inference Rules only.
  3. Use the method of Section 4.1 to prove
    |- (p q) (r s)        (p  q s) .
    You may use the hint for Problem (4.5) in the text.
  4. Apply the Deduction Theorem (i.e., use the method of assuming the antecedent) to prove
    |- (p q)        ((r p)   (r q)) .


File translated from TEX by TTH, version 2.60.
On 14 Oct 2000, 19:58.