U+2205 EMPTY SET
U+2205 was added to Unicode in version 1.1 (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 a Neutral East Asian Width. In bidirectional context it acts as Other Neutral and is not mirrored. The glyph can, under circumstances, be confused with 1 other glyphs. In text U+2205 behaves as Alphabetic regarding line breaks. It has type Other for sentence and Other for word breaks. The Grapheme Cluster Break is Any.
The Wikipedia has the following information about this codepoint:
In mathematics, and more specifically set theory, 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; in other theories, its existence can be deduced. Many possible properties of sets are trivially true for the empty set.
Null set was once a common synonym for "empty set", but is now a technical term in measure theory. The empty set may also be called the void set.
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-Escape | ∅ |
| Wrong windows-1252 Mojibake | â |
| HTML-Escape | ∅ |
| HTML-Escape | ∅ |
| HTML-Escape | ∅ |
| HTML-Escape | ∅ |
| digraph | /0 |
| alias | null set |
| LaTeX | \varnothing |
Related Characters
Confusables
Elsewhere
Complete Record
| Property | Value |
|---|---|
| Age (age) | 1.1 |
| Unicode Name (na) | EMPTY SET |
| Unicode 1 Name (na1) | — |
| Block (blk) | Math_Operators |
| General Category (gc) | Math Symbol |
| Script (sc) | Common |
| Bidirectional Category (bc) | Other Neutral |
| Combining Class (ccc) | Not Reordered |
| Decomposition Type (dt) | None |
| Decomposition Mapping (dm) |
 |
| Lowercase (Lower) | ✘ |
| Simple Lowercase Mapping (slc) |
|
| Lowercase Mapping (lc) |
|
| Uppercase (Upper) | ✘ |
| Simple Uppercase Mapping (suc) |
|
| Uppercase Mapping (uc) |
|
| Simple Titlecase Mapping (stc) |
|
| Titlecase Mapping (tc) |
|
| Case Folding (cf) |
|
| ASCII Hex Digit (AHex) | ✘ |
| Alphabetic (Alpha) | ✘ |
| Bidi Control (Bidi_C) | ✘ |
| Bidi Mirrored (Bidi_M) | ✘ |
| Bidi Paired Bracket (bpb) |
|
| Bidi Paired Bracket Type (bpt) | None |
| Cased (Cased) | ✘ |
| Composition Exclusion (CE) | ✘ |
| Case Ignorable (CI) | ✘ |
| Full Composition Exclusion (Comp_Ex) | ✘ |
| Changes When Casefolded (CWCF) | ✘ |
| Changes When Casemapped (CWCM) | ✘ |
| Changes When NFKC Casefolded (CWKCF) | ✘ |
| Changes When Lowercased (CWL) | ✘ |
| Changes When Titlecased (CWT) | ✘ |
| Changes When Uppercased (CWU) | ✘ |
| Dash (Dash) | ✘ |
| Deprecated (Dep) | ✘ |
| Default Ignorable Code Point (DI) | ✘ |
| Diacritic (Dia) | ✘ |
| East Asian Width (ea) | Neutral |
| Extender (Ext) | ✘ |
| FC NFKC Closure (FC_NFKC) |
|
| Grapheme Cluster Break (GCB) | Any |
| Grapheme Base (Gr_Base) | ✔ |
| Grapheme Extend (Gr_Ext) | ✘ |
| Grapheme Link (Gr_Link) | ✘ |
| Hex Digit (Hex) | ✘ |
| Hangul Syllable Type (hst) | Not Applicable |
| Hyphen (Hyphen) | ✘ |
| ID Continue (IDC) | ✘ |
| Ideographic (Ideo) | ✘ |
| ID Start (IDS) | ✘ |
| IDS Binary Operator (IDSB) | ✘ |
| IDS Trinary Operator and (IDST) | ✘ |
| InMC (InMC) | — |
| Indic Positional Category (InPC) | NA |
| Indic Syllabic Category (InSC) | Other |
| ISO 10646 Comment (isc) | — |
| Joining Group (jg) | No_Joining_Group |
| Join Control (Join_C) | ✘ |
| Jamo Short Name (JSN) | — |
| Joining Type (jt) | Non Joining |
| Line Break (lb) | Alphabetic |
| Logical Order Exception (LOE) | ✘ |
| Math (Math) | ✔ |
| Noncharacter Code Point (NChar) | ✘ |
| NFC Quick Check (NFC_QC) | Yes |
| NFD Quick Check (NFD_QC) | Yes |
| NFKC Casefold (NFKC_CF) |
|
| NFKC Quick Check (NFKC_QC) | Yes |
| NFKD Quick Check (NFKD_QC) | Yes |
| Numeric Type (nt) | None |
| Numeric Value (nv) | NaN |
| Other Alphabetic (OAlpha) | ✘ |
| Other Default Ignorable Code Point (ODI) | ✘ |
| Other Grapheme Extend (OGr_Ext) | ✘ |
| Other ID Continue (OIDC) | ✘ |
| Other ID Start (OIDS) | ✘ |
| Other Lowercase (OLower) | ✘ |
| Other Math (OMath) | ✘ |
| Other Uppercase (OUpper) | ✘ |
| Pattern Syntax (Pat_Syn) | ✔ |
| Pattern White Space (Pat_WS) | ✘ |
| Quotation Mark (QMark) | ✘ |
| Radical (Radical) | ✘ |
| Sentence Break (SB) | Other |
| Simple Case Folding (scf) |
|
| Script Extension (scx) | Common |
| Soft Dotted (SD) | ✘ |
| STerm (STerm) | ✘ |
| Terminal Punctuation (Term) | ✘ |
| Unified Ideograph (UIdeo) | ✘ |
| Variation Selector (VS) | ✘ |
| Word Break (WB) | Other |
| White Space (WSpace) | ✘ |
| XID Continue (XIDC) | ✘ |
| XID Start (XIDS) | ✘ |
| Expands On NFC (XO_NFC) | ✘ |
| Expands On NFD (XO_NFD) | ✘ |
| Expands On NFKC (XO_NFKC) | ✘ |
| Expands On NFKD (XO_NFKD) | ✘ |