# Are there any symbol to make a "half-space" in MathJax? half the size of $\text{\,}$ approx $\text{\kern 0.08333em}$?

Are there any symbol to make a half-space in MathJax? half the size of $$\text{\,}$$ approx $$\text{\kern 0.08333em}$$ ?

If I write jointly the letter $$\rho$$ with the "letter C with undertext letter D" $$C_D$$, and then the letters $$A$$ and letter $$v$$ (as for the formula of the Drag force), the result is $$\rho C_D A v$$ where the letter D ends being too far from the letter C compared with the position of $$\rho$$, as it where one different symbol $$\rho C$$ instead.

To separate them I introduced a space with $$\text{\,}$$ ending in $$\rho \,C_D A v$$, but due the proximity between letters $$A$$ and $$v$$ now looks like $$\rho$$ is a little far away, so I have the doubt if there exist a "half-space" symbol but I didn't found anything yet that do the trick.

I tried also with $$\text{\;\!}$$ with the following result $$\rho \;\!C_D Av$$ which looks better, but following what is said here:

$$\begin{array}{l} \text{\,} = 3\,\text{mu} \\ \text{\:} = 4\,\text{mu} \\ \text{\;} = 5\,\text{mu} \\ \text{\!} = -3\,\text{mu} \\ \Rightarrow \text{\;\!} = 2\,\text{mu} \neq 1.5\,\text{mu}\,\text{(half space \,)} \end{array}$$

so is not exactly half-space so maybe there is a symbol through it could be improved.

I found later the following:

$$\begin{array}{l} \text{\negmedspace} = -4\,\text{mu}\\ \Rightarrow \text{\;\negmedspace} = 1\,\text{mu} \neq 1.5\,\text{mu}\,\text{(half space \,)} \end{array}$$

which also isn't a half-space, but introduce a spacing of $$1\,\text{mu}$$ so it looks better (similar with the specing between letters $$A$$ and $$v$$): $$\rho \;\negmedspace C_D A v$$

Following the answer by @PeterPhipps it is possible to define the horizontal spacing at will, for example at half-space through $$\text{\hspace{0.08333em}}$$, which ends by looking as: $$\begin{array}{l l} \text{original - no spacing} & \rho C_D A v \\ \text{standard - \, spacing} & \rho\, C_D A v \\ \text{using \hspace{0.08333em}} & \rho\hspace{0.08333em} C_D A v \\ \text{using \;\negmedspace} & \rho\;\negmedspace C_D A v \\ \text{using \;\!} & \rho\;\! C_D A v \\ \end{array}$$

Looks like all also works on LaTex, but with \hspace there is a risk of having your formulas splitted at mid terms if a change of line happened, so instead you should use the following: \hspace*{0.08333em}

• @hardmath Thank for commenting. I wasn't able to find a symbol that has half-space to fill it with $\text{\phantom}$. But through the pages I found through this term I found the following: $\text{\;\negmedspace}$ which isn't a half-space, but introduce a spacing of $1\,\text{mu}$ so it looks better $$\rho \;\negmedspace C_D A v$$ Jul 8, 2022 at 20:43
• Maybe better asked on tex.stackexchange.com ? Jul 8, 2022 at 23:34
• The simple string "\rho C_D Av" crowds $ρ$ and $C$ close together because MathJax thinks you are spelling out a word with the two letters. One way to persuade it this is not your intention is to put the Greek letter in a separate "environment", e.g. "\operatorname{\rho} C_D Av" gives $\operatorname{\rho} C_D Av$. Jul 10, 2022 at 1:49

Maybe \hspace is what you require.

For example, $\rho \hspace{0.08333em}C$ produces $$\rho \hspace{0.08333em}C$$ as opposed to $$\rho C$$