U+1D559 "𝕙" Mathematical Double-Struck Small H Unicode Character

U+1D559 “𝕙” Mathematical Double-Struck Small H is a typographic symbol used primarily in mathematical notation to represent the letter "h" in a double‑struck font style, often associated with blackboard bold. This character belongs to the “Mathematical Alphanumeric Symbols” block and is intended for use in formal mathematical contexts where distinct letter styles denote specific sets or objects, such as representing a Hamiltonian or imaginary unit in advanced algebra and physics. It supports interoperability across digital platforms by providing a standard encoded character instead of relying on styling tricks like bold or italic formatting.

General Properties

Code Point	U+1D559
Version Added	3.1
Name	Mathematical Double-Struck Small H
Block	Mathematical Alphanumeric Symbols
General Category	Lowercase Letter
Canonical Combining Class	Not Reordered
Bidirectional Class	Left To Right
Decomposition Type	Font
Decomposition Mapping	"h" U+0068 Latin Small Letter H

Encodings

HTML Decimal Encoding	𝕙
HTML Hex Encoding	𝕙
UTF-8 Encoding	0xF0 0x9D 0x95 0x99
UTF-16 Encoding	0xD835 0xDD59
UTF-32 Encoding	0x0001D559
C/C++/Java Escape	\ud835\udd59

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	"h" U+0068 Latin Small Letter H
NFKC Simple Casefold	"h" U+0068 Latin Small Letter H
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	Lower