U+1D542 "𝕂" Mathematical Double-Struck Capital K Unicode Character

Unicode Version 17.0

𝕂

U+1D542 "𝕂" Mathematical Double-Struck Capital K is a stylized letterform belonging to the Mathematical Alphanumeric Symbols block, specifically designed for use in mathematical and scientific notation. Its double-struck, or blackboard bold, style originates from the tradition of writing certain letters with a doubled stroke to indicate number sets or mathematical objects, most famously ℕ, ℤ, ℚ, ℝ, and ℂ. While less common than those canonical examples, 𝕂 can be used to represent a field in abstract algebra, such as an arbitrary field in algebraic geometry or the base field in linear algebra, or to denote the real numbers in contexts like nonstandard analysis or the octonions. This character ensures a clear and distinct typographic representation within digital texts, allowing it to function as a precise symbol in equations and academic writing.

General Properties

Code Point U+1D542
Version Added 3.1
Name Mathematical Double-Struck Capital K
Block Mathematical Alphanumeric Symbols
General Category Uppercase Letter
Canonical Combining Class Not Reordered
Bidirectional Class Left To Right
Decomposition Type Font
Decomposition Mapping "K" U+004B Latin Capital Letter K

Encodings

HTML Decimal Encoding 𝕂
HTML Hex Encoding 𝕂
UTF-8 Encoding 0xF0 0x9D 0x95 0x82
UTF-16 Encoding 0xD835 0xDD42
UTF-32 Encoding 0x0001D542
C/C++/Java Escape \ud835\udd42

Unicode Properties

NFC Quick Check Yes
NFD Quick Check Yes
Numeric Type None
Numeric Value NaN
Line Break Alphabetic
Uppercase Yes
Cased Yes
Changes When NFKC Casefolded Yes
NFKC Casefold "k" U+006B Latin Small Letter K
NFKC Simple Casefold "k" U+006B Latin Small Letter K
Script Common
Script Extensions Common
Indic Syllabic Category Other
ID Start Yes
XID Start Yes
ID Continue Yes
XID Continue Yes
Alphabetic Yes
Math Yes
Other Math Yes
Vertical Orientation Rotated
Grapheme Base Yes
Grapheme Cluster Break Other
Word Break Alphabetic letter
Sentence Break Upper