[Tex/LaTex] How to type the symbol for usual topology $R_{(-)}$ in LaTex


How could I type the symbol as shown in the picture below?

I tried to use $\mathbb{R}_{(-)}$ instead, but the - inside can not touch the parenthesis on both sides.

I want to create a horizontal line that stops automatically when it touches the parenthesis.

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Best Answer

What about \leftfree \mkern -12mu \rightfree from MnSymbol package?

enter image description here

\[ \mathbb{R}_{\leftfree\mkern -12mu\rightfree} \]
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