I have defined `lemma`

and use it as follows:

```
\newtheorem{theorem}{Theorem}[section]
\newtheorem{lemma}[theorem]{Lemma}
...
\begin{lemma}
abc_\textbf{indice}
\end{lemma}
```

It turns out that the `indice`

becomes italic, does anyone know how to just make it bold, not italic?

## Best Answer

It won't look pretty, but you may switch off italics inside the Lemma by using

`\textup{\textbf{indice}}`

.EDIT: As egreg has commented,

`\mathbf`

may be a better choice.