Set Inequality
From ProofWiki
Theorem
- $S \ne T \iff \left({S \nsubseteq T}\right) \lor \left({T \nsubseteq S}\right)$
Proof
| \(\displaystyle \) | \(\displaystyle \) | \(\displaystyle \) | \(\displaystyle S \ne T\) | \(\iff\) | \(\displaystyle \neg \left({S = T}\right)\) | \(\displaystyle \) | \(\displaystyle \) | \(\displaystyle \) | |||
| \(\displaystyle \) | \(\displaystyle \) | \(\displaystyle \) | \(\displaystyle \) | \(\iff\) | \(\displaystyle \neg \left({\left({S \subseteq T}\right) \land \left({T \subseteq S}\right)}\right)\) | \(\displaystyle \) | \(\displaystyle \) | \(\displaystyle \) | Equality of Sets | ||
| \(\displaystyle \) | \(\displaystyle \) | \(\displaystyle \) | \(\displaystyle \) | \(\iff\) | \(\displaystyle \neg \left({S \subseteq T}\right) \lor \neg \left({T \subseteq S}\right)\) | \(\displaystyle \) | \(\displaystyle \) | \(\displaystyle \) | De Morgan's Laws | ||
| \(\displaystyle \) | \(\displaystyle \) | \(\displaystyle \) | \(\displaystyle \) | \(\iff\) | \(\displaystyle \left({S \nsubseteq T}\right) \lor \left({T \nsubseteq S}\right)\) | \(\displaystyle \) | \(\displaystyle \) | \(\displaystyle \) |
$\blacksquare$