Help with math problem

[KyoPhan]

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I haven't touched math in a while and I have no clue how to approach this problem. I don't really know what that upside down U means, but it looks familiar.

Does anyone know what this is called so I can get more info on it?

Thx
Edit: OO, I think they are asking what values they share in common?

 

[mh0000]

Yes, the upside down U is the symbol for the intersection of the two sets.