Take the following two equations:
\begin{equation}
o^{AR}_{i,t} = w^{AR}_i x_t + o^{AR}_{i+1,t-1}
\end{equation}
\begin{equation}
o^{MA}_{i,t} = w^{MA}_i x_t + o^{MA}_{i+1,t-1}
\end{equation}
The 'AR' and 'MA' are actually acronyms and are meant to be placed together with no gaps between them. I am aware that Math Mode treats each letter as an individual and doesn't kern them properly. This is particularly evident in the fact that the space between the 'M' and the 'A' is larger than between the 'A' and the 'R'.
Is there any way to get Math Mode to join the letters up more neatly?
\text{MA}
, or\mathrm{MA}
. For the difference between them see Is there a preference of when to use \text and \mathrm?.\DeclareMathOperator
in this case makes sense as they are not operators and don't act on other variables. A better solution might be to define a macro for them:\newcommand*{\MA}{\mathrm{MA}}
for example.