Subsets of a set containing an empty set.
68244
Is ∅ equivalent to {∅}?
81351
Polish space in which the interior of each compact set is empty
99480
Why is predicate "all" as in all(SET) true if the SET is empty?
84609
Unary intersection of the empty set
125502
Empty set literal?
110485
Nested sequence of non-empty compact subsets - intersection differs from empty set
44673
$M$ connected $\iff$ $M$ and $\emptyset$ are the only subsets of $M$ open and closed at the same time
118824
What is the complement of empty set?
65308
Axiom of Choice: Family of non-empty sets mutually disjoint or not?
148399
Two sets which contain each other as elements
110677
How is an empty set truly "empty"?
28523
When would the intersection of the empty set mean anything?
146364
$X$ is connected iff $\forall A\subset X,$ $\partial A\neq\emptyset$
109219
How do the sets $\emptyset\times B,\ A\ \times \emptyset, \ \emptyset \times \emptyset $ look like?
117658
A set with n elements has 2^n subsets
130418
Is ${\{\emptyset,\{\emptyset\},\{\{\emptyset\}\},\{\{\{\emptyset\}\}\},...\}} $ a set?
33064
Powerset of set with empty sets