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

William F Hammond hammond at csc.albany.edu
Fri Apr 1 19:15:40 CEST 2016

Hans Georg Schaathun writes:

> On Thu, Mar 31, 2016 at 10:51:23AM -0700, William F Hammond wrote:
>> I think the source is nonsense -- or, at best, ambiguous -- if translation
>> to HTML with MathML is envisioned.  For example, is this an abuse of math
>> because the user does not know about \textless or how to obtain U+2329?  If
>> it's indeed intended as math, is this an attempt to use \langle (U+27E8) as
>> an ordinary math symbol other than a group opener?  Or is it intended to be
>> the empty group properly marked up with
>> "\left\langle{}\right." ?
>
> I am not sure if I should take the question personally, or generally.
> But since my question probably triggered the issue, I'll put in two
> pennies on each account :-)

Certainly not personal.

See my last reply to Michal.

>> It's not clear what a sensible translation should be.
>
> I also do not know what a sensible translation should be,
> but two points should be noted.  Firstly, TeX was never
> designed for semantic markup, and enforcing new semantics
> on macroes is not a good idea if it can be avoided.

I agree.  Also neither TeX nor LaTeX were designed for
translation to html.

> Secondly, mathematical symbolism is neither static nor
> universal, except for a very small core.

Yes.

> \rangle and \langle may not be the most probably
> candidates to be redefined for an ad hoc purpose, but
> given the number of mathematicians and many narrow
> branches of the field, /someone/ is surely going to do
> just that at some point.

That /someone/ could be well-served by creating a suitable
LaTeX profile for his or her writing.  For more on my