Hi, thanks for the review.  Please find attached an updated patch.

> I guess so. OTOH, I assume latex environments are always math
> environments. One can use LaTex export blocks for "regular" LaTeX.
I left the math check in the attached patch for now.  Please let me know
if you would like me to remove it.

> Nitpick: since this is a predicate, it should be named
> `org-html--math-environment-p'.
Done.

> Meanwhile, I think the implementation is a bit convoluted. What about
> the following?
>
>     (replace-regexp-in-string
>      "\\`[ \t]*\\\\begin{\\([^*]+?\\)}"
>      "\\1*"
>      (replace-regexp-in-string "^[ \t]*\\\\end{\\([^*]+?\\)}[ \r\t\n]*\\'"
>                                "\\1*"
>                                latex-frag nil nil 1)
>      nil nil 1)
Done.

> IMO, this doesn't deserve to be a function, you can just use something
> like this:
>
>     (if (org-string-nw-p label)
>         (replace-regexp-in-string "\\`.*"
>                                   (format "\\&\n\\\\label{%s}" label)
>                                   latex-frag)
>       latex-frag)
Done.

Thanks,

thibault