From: Stephen Watt <smwatt@gmail.com>

Date: Tue, 26 Jul 2016 08:49:04 -0400

Message-ID: <CALozgsh8m09oSz-gGg90p8onxuA_q5KktYeakBU+LfMOzLkYPg@mail.gmail.com>

To: Frédéric WANG <fred.wang@free.fr>

Cc: "www-math@w3.org" <www-math@w3.org>

Date: Tue, 26 Jul 2016 08:49:04 -0400

Message-ID: <CALozgsh8m09oSz-gGg90p8onxuA_q5KktYeakBU+LfMOzLkYPg@mail.gmail.com>

To: Frédéric WANG <fred.wang@free.fr>

Cc: "www-math@w3.org" <www-math@w3.org>

Sorry, no. I did not mean expanding to plain text. I meant the leaf elements would be tagged. So the example is <mrow> <mo>[</mo> <mi>a</mi> <mo>,</mo> <mi>b</mi> <mo>[</mo> <mi>f</mi> <mo>]</mo> <mi>d</mi> <mo>,</mo> <mi>e</mi> <mo>]</mo> </mrow> or "an mrow containing [a, b [ f ] d, e]" for easier discussion. I almost agree with you and David that if you put in all the mrows (by hand or by code generation) then there is no information loss between an mfenced and a 3 element mrow. We would have to require that syntactically paired operators be given as the first and last elements of a three element mrow. But do we ALWAYS want three element mrows with first and last elements being operators to be treated as mfenced is? What about [ x ) or [ + ] or, my personal favourite, - x ! Secondly, can we really rely on all mathml to put in all the grouping mrows? We don't require it so I don't think we can count on it. We also have to allow for fence separators that stretch such as < x | Q | y > or ( a | b ). In the <x | Q | y> example, we would want the bars to stretch in the quantum mechanical case, but not if we were talking about the expected value of x times the absolute value of Q times y. So we would have to have <mrow> \langle x | Q | y \rangle </mrow> vs <mrow> \langle <mrow> x <mrow> | Q |</mrow> y </mrow> \rangle </mrow> where \langle and \rangle mean the relevant unicode points and leaf tagging is implied. What is the rule? An <mrow> with the first and last elements being operators all middle operators taken as separators? This works for < x | Q | y > but not for -x - y + 3! How would you handle these cases? Stephen On Tue, Jul 26, 2016 at 3:09 AM, Frédéric WANG <fred.wang@free.fr> wrote: > Le 26/07/2016 à 00:00, Stephen Watt a écrit : > > I see your point, but have to say that I am not really satisfied with > > the current spec language regarding equivalence. Mfenced can also > > give information about grouping that is lost with the mrow > > formulation, e.g. an mrow containining [a, b [ f ] d, e] may be a > > list of three things or a pair of half open intervals with an f in the > > middle. > So the only thing you are saying is that expanding to plain text without > explicit grouping implies loss of information compared to using mfenced. > That's true, but that's not my point. If you really follow the expansion > rules in MathML3 instead of using plain text then you see that nothing > is lost in your example and that the mfenced element is again useless. > > Certainly, one can write <mo>+<mrow> without proper grouping as that's > unfortunately often the case for markup generated from text > representation like TeX or ASCII. But the existence of an mfenced > element in MathML does not magically force converters or people to do > this grouping. > > >Received on Tuesday, 26 July 2016 12:49:33 UTC

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