I've been noticing that the org-pretty-entities code incorrectly lexes numbers as part of TeX command names; for example, if I type $\sim2n^2$, the \sim will not be replaced with a ~ because the 2 is lexed as part of the command name. This is incorrect; in TeX, numbers are not legal parts of a command name.
Here's a patch that fixes the issue:
diff --git a/lisp/org.el b/lisp/org.el index 73b1073..0db5a0b 100644 --- a/lisp/org.el +++ b/lisp/org.el @@ -5735,7 +5735,7 @@ needs to be inserted at a specific position in the font- (when org-pretty-entities (catch 'match (while (re-search-forward - "\\\\\\([a-zA-Z][a-zA-Z0-9]*\\)\\($\\|[^[:alnum:]\n]\\)" + "\\\\\\([a-zA-Z]+\\)\\($\\|[^[:alpha:]\n]\\)" limit t) (if (and (not (org-in-indented-comment-line)) (setq ee (org-entity-get (match-string 1)))