# Re: Is invisibleTimes mandatory? (Was Re: Profiling ...)

Date: Sat, 23 Dec 2006 04:41:54 -0800 (PST)
Message-ID: <3231.217.124.88.254.1166877714.squirrel@webmail.canonicalscience.com>
To: <www-math@w3.org>


William F Hammond said:

<juanrgonzaleza@canonicalscience.com> writes:

> In the first version of the input syntax for MathML i discussed here,
> stuff as entitities was represented as empty elements. Not just for MathML
> but also for XHTML. E.g. &oacute; was <oacute/> and next defined via
> Schema (no DTD).

> I don't see oacute as a math symbol; it's just another letter.

I was simply noticing there exists interest to reemplace entities outside
of MathML too. Schemas use way i said instead current DTD entities.

> In my experience one usually says "4 pi" rather than "4 times pi".

As said standard reading of math is "4" "times" "pi". "4" "pi" is
acceptable iff you know both 4 and pi are, but "f" "x" is ambiguous. What
does I mean by (K x y) = x?

> Are you saying that mathml-capable aural user agents commonly do not
> make a distinction between
>
>     <mi>x</mi><mi>y</mi>    and    <mi>xy</mi>   ?

I think that i was saying that cannot differentiate

<mi>x</mi><mi>y</mi>    from   <mi>x</mi><mi>y</mi>

> Perhaps a lame aural agent might fail in this regard.  But, on the
> other side, a lame visual agent might also fail by inserting an
> unknown symbol indicator for <mo>&invisibleTimes;</mo>.  (There is a
> history of this.)

Because problems with non-numerical entities or with the Unicode character
itself?

> Also the invisible times can be useful for automatic linebreaking.

> But doesn't it bind rather tightly?

Enough for the cuadratic formula [1].

> As an author if I think the context for using <mi>x</mi><mi>y</mi>
> might not be sufficient to imply invisibleTimes, then I will use
> something explicit like \cdot.

But authors on the web would write for others –including machines– not for
themselves.

I do not can see how you will avoid ambiguities on your files.

[1]  http://www.w3.org/TR/MathML/chapter2.html#fund.pres

Received on Saturday, 23 December 2006 12:42:02 GMT

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