# [tex4ht] [bug #278] Wrong mathml with $\langle$

William F Hammond hammond at csc.albany.edu
Fri Apr 1 18:30:11 CEST 2016

Michal --

You write:

> It is based on earlier message from today, where OP used
> it for encoding brackets around email address. It could be
> seen (and I agree that it is) as abusing of math mode, but
> this construct seems as quite common when I googled it.

Yes, it is far too common.  As I said, when translation to
html with math is in the picture, it should be regarded as
wrong.  That is because everything in math mode will be
translated to something that is mathematical and, as such,
presumably meaningful as content for pasting into
mathematical software.

For angle-bracketing an email address one may use \url
(or \nolinkurl) from the hyperref package.

> As I am not a math expert, I am not sure whether is it
> legitimate to use this in math or not. If it isn't and it
> is really just dirty hack to get angles in text, then we
> maybe just should educate users that it is wrong. But in
> this case we may get occasional bug reports about invalid
> tex4ht output from users following advice on the internet
> :)

Given that users are inclined not to read manuals, I don't
know how to educate them except with error messages that
they can understand.

Of course, one is stuck with Knuth's choice for the use of
'<' and '>' outside of math (unless one invokes a package),
but one can certainly design a LaTeX profile in which the
default non-math meaning of '<' and '>' would allow
"<abc at foo.net>" to work as a bracketed email address (in the
current font), and yet still be able to reformulate the
document for typesetting by latex.

-- Bill