Lesson 17 of 48
Sets
Union, intersection, complement — and the language everything else is written in.
Sets are how mathematics says “this collection” without saying how it is stored. And the operations turn out to be lesson 15 again: union is OR, intersection is AND, complement is NOT.
Do this
Prove one of De Morgan's laws twice — once by element-chasing in both directions, once by truth table — and notice that they are the same proof.
The question that unlocks the next lesson
The complement of (A ∪ B) equals…
- Acomplement(A) ∪ complement(B)
- Bcomplement(A) ∩ complement(B)
- CA ∩ B
- Dcomplement(A ∩ B)