Why is the intersection of the empty set the universe?
36881
Empty intersection and empty union
106455
intersection of infinite collection of finite sets?
121847
Don't we need the axiom of choice to choose from a non-empty set?
136108
Arbitrary intersection of closed, connected subsets of a compact space connected?
39020
Why is empty set an open set?
16056
Is empty set element of every set if it is subset of every set?
114786
Question about Infimum. (conclusion about intersection)
65768
What is the cardinality of the set of the empty set?
44623
Closed set as a countable intersection of open sets
109219
How do the sets $\emptyset\times B,\ A\ \times \emptyset, \ \emptyset \times \emptyset $ look like?
660
Is the empty space really empty?
113377
Empty preimage of an intersection implies empty intersection of the preimages
130156
Image of the union and intersection of sets.
125957
What is the product of the empty set?
113640
Why is there this strange contradiction between the language of logic and that of set theory?
97951
Is the void set (∅) a proper subset of every set?
89712
For every set $A$, the empty set is a subset of $A$. The empty set is a set. Therefore, the empty set has a cardinality $\geq 1\ldots$