# Questions tagged [natural-deduction]

For questions concerning natural deduction, a formal proof system studied in proof theory. A natural deduction proof starts with a set of premises and applies introduction and elimination rules to arrive at the conclusion. This tag is not specific to any particular logic, classical or intuitionistic, propositional or allowing quantifiers.

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### Help proving $\lnot$(G $\rightarrow$ $\lnot$A) $\vdash$ G.

I'm have been working on a natural deduction assignment for a couple of days and I went yesterday to ask my teacher for help but he gave me no helpful information so I'm asking here. I have tried a ...
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### Proof of distributivity of $\land$ over $\lor$ using disjE in natural deduction

I'm learning about natural deduction from https://www.inf.ed.ac.uk/teaching/courses/ar//slides02.pdf I'm trying to understand its proof of $$P \land (Q \lor R) \vDash (P \land Q) \lor (P \wedge R)$$ ...
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### How do we know inference rules are correct?

I know axioms are statements which are assumed to be true (meaning that axioms are not proved). Theorems are statements which can be proved or has been proved. In the proofs of theorems we can use ...
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