Intersection and union of no sets

We all know how to define the intersection and union of an arbitrary family of subsets \{A_i\}_{i \in I} of a set A. But what if the index set I is empty, i.e. what exactly are union and intersection of “no sets”?

[Answer: Next time. I guess most of the readers know the answer!]

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About Ken Leung

I'm a ordinary boy who likes Science and Mathematics.
This entry was posted in Set Theory. Bookmark the permalink.

One Response to Intersection and union of no sets

  1. wongting says:

    I think I know the answer provided that we use a “universal set” (the largest set under consideration). But are there some subtle issues?

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