Problem:
Find the number of pairs of union/intersection operations satisfying the following condition: for any sets , function , and subsets of , we have equality of sets
where denotes the image of : the set , which is a subset of . The images (of ) and (of ) are similarly defined.
Solution
Solution:
Answer: 1 If and only if . See http://math.stackexchange.com/questions/359693/overview-of-1
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