U+1D55B "𝕛" Mathematical Double-Struck Small J Unicode Character
Unicode Version 17.0
𝕛
U+1D55B "𝕛" Mathematical Double-Struck Small J is a typographical glyph from the Mathematical Alphanumeric Symbols block, designed to represent the lowercase letter J in a double struck or blackboard bold style. This style is commonly used in mathematics and theoretical physics to denote specific sets, such as the imaginary unit or a vector space, and it is part of a broader set of double struck letters used to distinguish mathematical objects from ordinary text. Unlike regular text characters, this symbol has a formal, open outline appearance that helps avoid confusion with similar looking letters in complex equations.
General Properties
| Code Point | U+1D55B |
| Version Added | 3.1 |
| Name | Mathematical Double-Struck Small J |
| Block | Mathematical Alphanumeric Symbols |
| General Category | Lowercase Letter |
| Canonical Combining Class | Not Reordered |
| Bidirectional Class | Left To Right |
| Decomposition Type | Font |
| Decomposition Mapping | "j" U+006A Latin Small Letter J |
Encodings
| HTML Decimal Encoding | 𝕛 |
| HTML Hex Encoding | 𝕛 |
| UTF-8 Encoding | 0xF0 0x9D 0x95 0x9B |
| UTF-16 Encoding | 0xD835 0xDD5B |
| UTF-32 Encoding | 0x0001D55B |
| C/C++/Java Escape | \ud835\udd5b |
Unicode Properties
| NFC Quick Check | Yes |
| NFD Quick Check | Yes |
| Numeric Type | None |
| Numeric Value | NaN |
| Line Break | Alphabetic |
| Lowercase | Yes |
| Cased | Yes |
| Changes When NFKC Casefolded | Yes |
| NFKC Casefold | "j" U+006A Latin Small Letter J |
| NFKC Simple Casefold | "j" U+006A Latin Small Letter J |
| Script | Common |
| Script Extensions | Common |
| Indic Syllabic Category | Other |
| ID Start | Yes |
| XID Start | Yes |
| ID Continue | Yes |
| XID Continue | Yes |
| Soft Dotted | Yes |
| Alphabetic | Yes |
| Math | Yes |
| Other Math | Yes |
| Vertical Orientation | Rotated |
| Grapheme Base | Yes |
| Grapheme Cluster Break | Other |
| Word Break | Alphabetic letter |
| Sentence Break | Lower |