In the markdown file, I try to write my in-line math equations in the $$.

But there must be something wrong when I use the _ for subscript in two in-line equations.

the engine of the GitHub markdown file will explain them as an italic font text, not two equations.

But my markdown preview in VS Code shows it well.

Sample:

the origin text:

math sample $a_i$ and $b_i$ and $hat{p}_{sigma(i)}(c_i)$ and $mathcal{L}_{box}(b_i,hat{b}_{sigma(i)})$.

the GitHub result:

github result

the same result in stackoverflow under:

math sample $a_i$ and $b_i$ and $hat{p}{sigma(i)}(c_i)$ and $mathcal{L}{box}(b_i,hat{b}_{sigma(i)})$.

you see the underline _ after hat{} and mathcal{} are explained to italic text.

my VS Code preview result:

my VS Code preview result