why intersection of empty class of sets is the whole space while their union is null set?(adsbygoogle = window.adsbygoogle || []).push({});

Book writes that an element will fail to be in the intersection if it fails to be in one of the sets of the class but since there is nothing in the empty class so there is nothing in the empty class that contradicts that an element does not belong to the intersection so in this way intersection is the whole space. ASSUME THIS IS TRUE. Then why don't they use the same arguments for the union? Then union should also have been the whole space......

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# Union and Intersection of empty class of sets

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