New posts in Natural Deduction

Understanding ex falso quodlibet together with proof by contradiction in a Gentzen style ND Proof

Trouble understanding proof to $\vdash ((\neg(\phi\rightarrow \psi))\rightarrow\phi)$?

Predicate Logic, Proof of validity . How to remove negation infront of existential quantifier?

Is this proof correct? (natural deduction)

Prove the undecidability of a formula

Are the two Or-Elims equivalent?

Use Fitch system to proof ((p ⇒ q) ⇒ p) ⇒ p without any premise. ONLY FOR FITCH SYSTEM.

"Modus moron" rule of inference?

Does double negation distribute over disjunction intuitionistically?

Difference between Logical Axioms and Rules of Inference