[whatwg] Physical quantities: <var> or <i>?

[Aryeh Gregor]

On Thu, Apr 14, 2011 at 10:02 AM, Jukka K. Korpela <jkorpela at cs.tut.fi> wrote:
> Looking at the nice summary (with examples) of text-level markup at
> http://www.whatwg.org/specs/web-apps/current-work/multipage/text-level-semantics.html#usage-summary
> I started wondering why there is no example of markup for symbols of
> physical quantities. The descriptions of individual elements or their
> examples don't seem to say anything about this either.
>
> So what markup should we use for E = mc², given that by the applicable
> standards, E, M, and c should appear in italics and the other characters as
> normal (upright)?

Those three characters are typeset, read, and otherwise presented
identically to variables, so the correct tag is <var>.  Perhaps the
spec could be clearer on this point.