I want to type the π symbol in Mathjax (physics.stackexchange) without having to copy the Ascii character. I found https://tex.stackexchange.com/questions/204998/double-struck-zero-and-one which mentioned
\mathbbm{1}
\mathds{1}
\mathbb{1}
The first two options don't work and the last option looks like a regular 1. Since it's on stackexchange I can't import modules as far as I know.
This is nearly a dupe but seeing how no one voted to close maybe I can try to summarise the information better than the exploratory post there. AFAIK the current options are
| Description | Input | Output |
|---|---|---|
| Copy paste the Unicode symbol π | $π$ |
$π$ |
The naive \mathbb1 (not reccomended: only works with some setups e.g. HTML-CSS renderer on machines with the STIX fonts installed) |
$\mathbb1$ or $\Bbb1$ |
$\mathbb1$ or $\Bbb1$ |
Memorise the hexadecimal number that encodes π, x1D7D9 (the Ds are case insensitive) |
$\unicode{x1D7D9}$ |
$\unicode{x1d7d9}$ |
Place one of the above in a \newcommand |
$\newcommand{\one}{\unicode{x1d7d9}}$, then $\one$ |
$\newcommand{\one}{\unicode{x1d7d9}}\one$ |
A possible alternative to using \newcommand would be to use some sort of clipboard feature. (This may involve installing software.) For instance Macs come with a system wide text replacement feature built-in; so one can make something like mseone automatically turn into \unicode{x1d7d9}; some details are in this answer.
The following 'substitutes' are easier to use:
| Input | Output |
|---|---|
$\mathbf1$or $\bf1$ |
$\mathbf1$ or $\bf1$ |
$\pmb1$ or $1\!\!1$ |
$\pmb1$ or $1\!\!1$ |
$1\!\rm l$ (variant of the above) |
$1\!\rm l$ |
One can get creative e.g. \pmb can be iterated: $\pmb{\pmb{\pmb{\pmb{1}}}}$ but if you're going to do something hard, you might as well use \unicode{x1D7d9}.
Since $1+2=3$ and x1D7D9+2=x1D7DB, the code $\unicode{x1D7DB}$ outputs $\unicode{x1D7DB}$.
Having \mathbb1 be equivalent to the Unicode input \unicode{x1d7d9} is a planned feature of Mathjax v3, but (IIRC) at the time of writing Mathematics SE does not have plans to use Mathjax v3.
Perusing a table of characters, here is a non-exhaustive list of other mathematical Unicode symbols that I do not know the equivalent Mathjax code for that nonetheless display well for me in Safari v14.0.3 on my Mac (but some have obvious substitutes):
| Description | Output |
|---|---|
| variant integral signs | $β―β°β¨β±β²β³β¨β¨β¨β¨β¨β¨β¨β¨β¨β¨β¨$ |
| variant equality symbols | $ββββββββββββββββββββββ£β$ |
| variant binary operators/relations | $ββββββββββββββββ β‘β¨β¨β¨΄β¨΅β¨Άβ¨·β¨Έβ¨Ήβ¨Ίβ¨»$ |
degree symbol 5Β° (distinct from ^\circ$^\circ$ or ^o$^o$) |
$5Β°$ |
| greek or lowercase in blackboard-bold | $βΏβ β½πππππππππππππππ π‘π’π£π€π₯π¦π§π¨π©πͺπ«$ |
(not included in the list: \iiiint, \oint $\iiiint,\oint$, \cong, \simeq, \equiv$\cong,\simeq,\equiv$, \otimes, \oplus, \ominus, \odot, \bigoplus, \bigotimes, \bigodot $\otimes,\oplus,\ominus,\odot,\bigoplus ,\bigotimes,\bigodot$.)
Some of them need extra code; consider β¨_{a\in\Lambda} U_a vs β¨\limits_{a\in\Lambda} U_a $$β¨_{a\in\Lambda} U_a \quad \text{vs}\quad β¨\limits_{a\in\Lambda} U_a$$
\unicode{x1d7d9}) and have them paste this in your text field when you type a keyword. Iβve added this to the answer (but unfortunately I donβt know of specific programs for this outside of a built in feature of Mac OS; βthere must be an app for thatβ. Suggestions welcome)
$\endgroup$
Mar 16, 2021 at 4:58
$\mathbb{1}$seems to do the job: $\mathbb{1}$. That being said, MathJax is not TeX, and does not support all of the features that a real TeX or LaTeX implementation supports. $\endgroup$\unicode{x1D7D9}$\unicode{x1D7D9}$ which can be wrapped in a newcommand $\endgroup$$\mathbb{1}$works only if I change the Math Renderer to MathML. (Firefox 86.0.1 on Windows 7.) $\endgroup$