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Theorem 1.1.4: De Morgan's Laws

i.e. the complement of the intersection of any number of sets equals the union of their complements.

i.e. the complement of the union of any number of sets equals the intersection of their complements.

Proof:

We will prove two set-inequalities to prove equality of the left and right hand sides. The proof of the second De Morganís law is left as an exercise.

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