What ⤀ means
It marks a partial surjection. Some inputs can lack results, yet every target value is reached.
⤀ is an infix operator in MathML, a web language for formulas, placed between values in the 2025 Core specification. Unicode proposals from 1999–2000 label it for Z notation; it entered Unicode in 2002. Those dates track encoding, not the notation's origin.
Formal mathematical notation, especially Z.
Do not read the heads as ordinary two-way travel.
Don't confuse it with
2
Related characters
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Questions people ask
1Why does ⤀ show as a box on some devices?
Because that device's fonts have no glyph for it. The character is still correct and still copies correctly — the box is a missing glyph, not a broken character.
More like this
10
How to type or find ⤀
- Also called
- partial surjection arrow · Z notation arrow
- Search it as
- Z notation · partial surjection
- Shows up in
- Anything that takes text · its shape is whatever your font draws
Windows (Word)
Windows
macOS
HTML
⤀CSS
\2900Code / HTML
Use \u2900 in code with Unicode escapes, or ⤀ / ⤀ in HTML.
Codes and encoding1 code points
HTML decimal
⤀
HTML hex
⤀
CSS content
content: "\2900";
Each escape is closed by the next backslash; a trailing space is needed before a literal hex digit.
URL encoded
%E2%A4%80
1
On screen
1
Code points
1
JS .length
3
UTF-8 bytes
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.