80-211                                                                                                             Spring 2003

 

 

Assignment #6

Due on Friday, February, 28th .

 

 

1. Do problems (n), (q), (s), (u) on page 103 of your text.

 

2. Using primitive rules or derived rules of the propositional calculus do problems (a), (c), (e) and (f) in exercise 2(i) on page 110 of your text.

 

3. Prove the following sequents using primitive rules or derived rules of the predicate and propositional calculus.

 

(a) "x(Gx → (Hx v ~Kx)), "x(Gx) ├ "x((Fx→Hx) v (Kx→Fx))

 

(b) "x(Gx→ (Hx & Fx)),  ~Hm  ├ ~Gm