U+2205 Empty Set
U+2205 was added in Unicode version 1.1 in 1993. It belongs to the block
This character is a Math Symbol and is commonly used, that is, in no specific script. The character is also known as null set.
The glyph is not a composition. It has no designated width in East Asian texts. In bidirectional text it acts as Other Neutral. When changing direction it is not mirrored. The word that U+2205 forms with similar adjacent characters prevents a line break inside it. The glyph can be confused with one other glyph.
The CLDR project calls this character “empty set” for use in screen reading software. It assigns these additional labels, e.g. for search in emoji pickers: mathematics, set operator.
The Wikipedia has the following information about this codepoint:
In mathematics, the empty set is the unique set having no elements; its size or cardinality (count of elements in a set) is zero. Some axiomatic set theories ensure that the empty set exists by including an axiom of empty set, while in other theories, its existence can be deduced. Many possible properties of sets are vacuously true for the empty set.
Any set other than the empty set is called non-empty.
In some textbooks and popularizations, the empty set is referred to as the "null set". However, null set is a distinct notion within the context of measure theory, in which it describes a set of measure zero (which is not necessarily empty).
Representations
System | Representation |
---|---|
Nº | 8709 |
UTF-8 | E2 88 85 |
UTF-16 | 22 05 |
UTF-32 | 00 00 22 05 |
URL-Quoted | %E2%88%85 |
HTML hex reference | ∅ |
Wrong windows-1252 Mojibake | ∅ |
HTML named entity | ∅ |
HTML named entity | ∅ |
HTML named entity | ∅ |
HTML named entity | ∅ |
alias | null set |
LATEX | \varnothing |
Adobe Glyph List | emptyset |
digraph | /0 |
Related Characters
Confusables
Elsewhere
Complete Record
Property | Value |
---|---|
1.1 (1993) | |
EMPTY SET | |
— | |
Mathematical Operators | |
Math Symbol | |
Common | |
Other Neutral | |
Not Reordered | |
none | |
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|
✘ | |
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|
|
|
✘ | |
|
|
|
|
|
|
|
|
|
|
✘ | |
✘ | |
✘ | |
✘ | |
✘ | |
✘ | |
✘ | |
✘ | |
✘ | |
✘ | |
✘ | |
✘ | |
✘ | |
✘ | |
✘ | |
✘ | |
✘ | |
✘ | |
✘ | |
✘ | |
✘ | |
✘ | |
✘ | |
✘ | |
✘ | |
|
|
Any | |
✔ | |
✘ | |
✘ | |
✘ | |
✘ | |
✘ | |
✘ | |
✘ | |
✘ | |
0 | |
0 | |
0 | |
✘ | |
None | |
— | |
NA | |
Other | |
— | |
✘ | |
✘ | |
✔ | |
✘ | |
Yes | |
Yes | |
|
|
Yes | |
|
|
Yes | |
✘ | |
✘ | |
✘ | |
✘ | |
✘ | |
✘ | |
✘ | |
✘ | |
✘ | |
✔ | |
✘ | |
✘ | |
✘ | |
✘ | |
Other | |
✘ | |
✘ | |
✘ | |
✘ | |
✘ | |
Other | |
✘ | |
✘ | |
✘ | |
✘ | |
✘ | |
✘ | |
✘ | |
|
|
None | |
neutral | |
Not Applicable | |
— | |
No_Joining_Group | |
Non Joining | |
Alphabetic | |
none | |
not a number | |
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|
R |