What 𝕆 means
The formula defines its reading. It can name the octonions, an eight-dimensional number system where grouping three factors differently can change the result. John T. Graves called them “octaves” in a letter dated Dec. 26, 1843; Arthur Cayley published them in 1845. A priority dispute left “Cayley numbers” as another name.
Blackboard bold began on chalkboards: doubling a stroke made bold math letters stand out, and that handwriting shaped print. The style often marks sets. In LaTeX, \mathbb{O} writes this O.
Don't confuse it with
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Questions people ask
1Why does 𝕆 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
11
Collections with 𝕆
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How to type or find 𝕆
- Search it as
- octonions · mathbb o · blackboard bold · double-struck o · octonion symbol
- Shows up in
- Anything that takes text · its shape is whatever your font draws
𝕆\1D546amsfonts or amssymb, then use \mathbb{O} in math mode.Codes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.