Marinada '25

[lang=hr] Sada ćemo naučit dvije stvari. A to su $\lnot p$ što je isto kao i $p \to \text {False}$ kao i $0$ što možete koristiti kada imate kontradikciju u pretpostavkama kao što je $p$ i $\lnot p$. Sada s ovim novim znanjem dokažite $$p \to \lnot \lnot p.$$ [/lang] [lang=en] Now we will learn two things. They are $\lnot p$, which is the same as $p \to \text{False}$, and $0$, which you can use when you have a contradiction in the assumptions such as $p$ and $\lnot p$. Now, with this new knowledge, prove $$p \to \lnot\lnot p .$$ [/lang]