An empty set is always a subset of another set, but can it also be an element of a set too?
123498
Is "empty set" an element of a set?
44673
$M$ connected $\iff$ $M$ and $\emptyset$ are the only subsets of $M$ open and closed at the same time
31376
If null set is an element of a set then will it belongs to set or subset?
144181
Given an arbitrary set $X$, can one always find an element outside $X$?
130418
Is ${\{\emptyset,\{\emptyset\},\{\{\emptyset\}\},\{\{\{\emptyset\}\}\},...\}} $ a set?
51434
What does the symbol $\subset\subset$ mean?
62208
If $A$ is a non-empty set, then $A \notin A$
134999
Writing empty set as union of basis elements for a topology.
102136
How many subsets contain no consecutive elements?
148399
Two sets which contain each other as elements
3392
Sum of products of elements of nonempty subsets of A set
39020
Why is empty set an open set?
146098
Number of nonempty subsets of a set with $n$ elements
146364
$X$ is connected iff $\forall A\subset X,$ $\partial A\neq\emptyset$
858
Is $\{\emptyset\}$ a subset of $\{\{\emptyset\}\}$?
88205
How can I define a topology on the empty set?
140668
Union of $2$ set $A, B$ where $ A$ is a subset of $B$