Why is $ \emptyset$ considered a set?
46317
What is an Empty set?
27107
intersection of the empty set and vacuous truth
103314
Let $\{K_n \}_{n \in \mathbb{N}}$ be a collection of sets, where $K_n = [n, \infty)$. Why is $\bigcap_{n \in \mathbb{N}} K_{n}$ empty?
39020
Why is empty set an open set?
27025
How do I choose an element from a non-empty set?
22482
How can an ordered pair be expressed as a set?
20140
Example of set which contains itself
26008
Why there is a unique empty set?
19138
If every object in math can be reduced to sets, how are tuples explained via sets?
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 $\geq 1\ldots$
71976
Is every element on a set also a set?
55995
Why is the supremum of the empty set $-\infty$ and the infimum $\infty$?
5230
Why can a 1 element set be a member of another set but not a subset of it?
30660
Empty set does not belong to empty set
28523
When would the intersection of the empty set mean anything?
58285
Is it true that if $X$ is connected, then for every nonempty proper subset $A$ of $X$, we have $\mathbf{Bd} \ne \emptyset$
110669
Linear span of the empty set