21.01.2015 Views

Elementary Logic

Elementary Logic

Elementary Logic

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

Natural Deduction (cont.)<br />

Γ, A ⊢ B (→I )<br />

Γ ⊢ A → B<br />

Γ ⊢ A → B<br />

Γ ⊢ B<br />

Γ ⊢ A (→E)<br />

Γ, A ⊢ B ∧ ¬B (¬I )<br />

Γ ⊢ ¬A<br />

Γ ⊢ A Γ ⊢ ¬A (¬E)<br />

Γ ⊢ B<br />

Γ ⊢ A (¬¬I )<br />

Γ ⊢ ¬¬A<br />

Γ ⊢ ¬¬A (¬¬E)<br />

Γ ⊢ A<br />

These inference rules collectively are called System ND (the<br />

propositional part).<br />

Yih-Kuen Tsay (SVVRL @ IM.NTU) <strong>Elementary</strong> <strong>Logic</strong> FLOLAC 2011 29 / 64

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!