# [OS X TeX] Re: A little help needed (math formula problem)

Berend Hasselman bhh at xs4all.nl
Sat Dec 19 12:56:29 CET 2009

On 19-12-2009, at 12:41, Juan Luis Varona wrote:

> Ross Moore <ross at ...> writes:
>
>>
>> the 'differential d' at the end of the integrals could be
>>         made upright (e.g. \,\phi\mathrm{d}\phi )
>>
>
> I don't like to use \mathrm{d} dor differentials
> (nor \mathrm{e} and \mathrm{i} for the numbers e and i).
> I always use \,dx, for instance.
>
> In my opinion, it is not the tradition in English or Spanish books
> to use upright d, e, or i.
> Perhaps it is only a tradition in French.

I very much prefer upright d, e and i.

See the article "Typesetting mathematics for science and technology according to ISO/31XI"
on http://www.tug.org/TUGboat/Contents/contents18-1.html

(especially page 40 and 41 item 6)
I always recommend people to use them upright to make the meaning perfectly clear.

Berend