Math CentralQuandaries & Queries


Question from Jim, a student:

Suppose A and B are sets and (A union B) = (A intersect B). Is it true that A=B.

Hi Jim,

You can prove that A = B by showing that A ⊂ B and B ⊂ A. Start with showing that A ⊂ B.

Let x ε A then x ε A ∪ B. Can you proceed from here?


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