Mia fuller
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- Joined
- Mar 5, 2017
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Hi everyone, does anyone know how you would work out the solutions to these questions would be? I am really struggling with this particular piece of homework, so would appreciate any help or explanations. I have to prove that the following statements are valid in logic. The numbers in brackets at the side represent how many lines the answer should be. It's taken from Paul tomassi's logic. Thank you
¬ = not → = if/ then
¬ ¬(P & Q) : ¬ ¬ (Q & P) (6)
¬ P → ¬Q: Q → P (6)
: (P →Q) → (¬Q →¬P) (5) Principle of transposition
Q → R : (¬Q →¬P) →(P →R) (9)
(P & Q) →¬R : R →(P →¬Q) (11)
P: [(¬(Q → R) →¬P)] →[( ¬R →¬Q)] (9)
P, ¬Q: ¬ (P →Q) (6)
P, ¬P : Q (8)
: ¬P → (P →Q) (10) Law of Dun Scotus
P → ¬P : ¬P (11)
¬ = not → = if/ then
¬ ¬(P & Q) : ¬ ¬ (Q & P) (6)
¬ P → ¬Q: Q → P (6)
: (P →Q) → (¬Q →¬P) (5) Principle of transposition
Q → R : (¬Q →¬P) →(P →R) (9)
(P & Q) →¬R : R →(P →¬Q) (11)
P: [(¬(Q → R) →¬P)] →[( ¬R →¬Q)] (9)
P, ¬Q: ¬ (P →Q) (6)
P, ¬P : Q (8)
: ¬P → (P →Q) (10) Law of Dun Scotus
P → ¬P : ¬P (11)