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Prove $S_1 = S_2$ if and only if

$(S_1 \cap S_2') \cup (S_1' \cap S_2) = \emptyset$

I get why it is, I just don't know how to write formal proofs.

$S_2'$, $S_1'$ in this modified notation means it has a line over it.

Thanks

5 Answers 5