(This question is close to scalebox / resizebox shifts fraction component, but the answer there provided did not fixed my issue)
When using scalebox, in a subscript, inside a fraction, it seems to weird out other elements in the fraction. This is my example:
I need a shorter minus sign, for this I define
\newcommand{\unaryminus}{\scalebox{0.4}[1.0]{\( - \)}}
And now I tried to use it inside a fraction, as a subscript
\frac{\gamma_{1,\unaryminus 1}{+}\gamma_{2,0}{+}\gamma_{3,1}}{3}
which gives

