U+2140 "⅀" Double-Struck N-Ary Summation Unicode Character

Unicode Version 17.0

U+2140 "⅀" Double-Struck N-Ary Summation is a typographic variant of the standard summation symbol (Σ) used in mathematical notation, rendered in a blackboard bold or double-struck style to indicate a sum over a set of numbers in contexts where a distinct visual emphasis is needed. Unlike the ordinary Greek capital letter sigma used for summation, this character is specifically encoded as a separate double-struck glyph, often appearing in academic or typeset documents to represent a summation operator with a more formal or decorative appearance, particularly in disciplines like algebra or number theory where notation clarity is paramount. It belongs to the Letterlike Symbols block in Unicode and is distinct from both the regular summation sign and other similar double-struck characters, serving as a specialized tool for mathematicians and typographers.

General Properties

Code Point U+2140
Version Added 3.2
Name Double-Struck N-Ary Summation
Block Letterlike Symbols
General Category Math Symbol
Canonical Combining Class Not Reordered
Bidirectional Class Other Neutral
Mirrored Yes
Decomposition Type Font
Decomposition Mapping "∑" U+2211 N-Ary Summation

Encodings

HTML Decimal Encoding ⅀
HTML Hex Encoding ⅀
UTF-8 Encoding 0xE2 0x85 0x80
UTF-16 Encoding 0x2140
UTF-32 Encoding 0x00002140
C/C++/Java Escape \u2140

Unicode Properties

NFC Quick Check Yes
NFD Quick Check Yes
Numeric Type None
Numeric Value NaN
Line Break Alphabetic
Changes When NFKC Casefolded Yes
NFKC Casefold "∑" U+2211 N-Ary Summation
NFKC Simple Casefold "∑" U+2211 N-Ary Summation
Script Common
Script Extensions Common
Indic Syllabic Category Other
Math Yes
Vertical Orientation Rotated
Grapheme Base Yes
Grapheme Cluster Break Other
Word Break Other
Sentence Break Other