is {{}} or {Ø} an empty set?
30660
Empty set does not belong to empty set
46317
What is an Empty set?
93501
Order of precedence of set operators
127664
Inverse elements in the absence of identities/associativity.
123498
Is "empty set" an element of a set?
62542
Why is the empty set considered an interval?
65549
What is the cartesian product of an empty set of sets?
97025
Can I get $$...$$ to behave like \[...\]?
16056
Is empty set element of every set if it is subset of every set?
33064
Powerset of set with empty sets
65768
What is the cardinality of the set of the empty set?
4442
What is the { get; set; } syntax in C#?
143003
$\bigcup \emptyset$ is defined but $\bigcap \emptyset$ is not. Why?
89873
PHP: a short cut for isset and !empty?
1307
Infimum and supremum of the empty set
128255
Empty Strings: Why or when is '' equal to ' '?
45508
Is the empty set a group?