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 nonempty.
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 
UTF8  E2 88 85 
UTF16  22 05 
UTF32  00 00 22 05 
URLQuoted  %E2%88%85 
HTML hex reference  ∅ 
Wrong windows1252 Mojibake  âˆ… 
HTML named entity  ∅ 
HTML named entity  ∅ 
HTML named entity  ∅ 
HTML named entity  ∅ 
alias  null set 
L^{A}T_{E}X  \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  


✘  




✘  










✘  
✘  
✘  
✘  
✘  
✘  
✘  
✘  
✘  
✘  
✘  
✘  
✘  
✘  
✘  
✘  
✘  
✘  
✘  
✘  
✘  
✘  
✘  
✘  
✘  


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  


R 