- From: Patrick Ion <ion@ams.org>
- Date: Thu, 23 Feb 2012 11:42:11 -0800
- To: www-math@w3.org, mathjax-dev@googlegroups.com
- Message-ID: <4F469693.1010006@ams.org>

I am puzzled that it would be thought that the base, the first argument of an element of type <mover>, <munder> or <munderover> might be expected to change its size automatically depending on the embellishment. That seems to be what's being asked for in the examples. If that isn't the intention then I think the sizes to be expected are already well defined by the default sizes of the construction's base elements. See http://www.w3.org/TR/MathML3/chapter3.html#3.1.3.2 Patrick P.S. Murray's first message and example displayed perfectly for me in Thunderbird 10.0.2 on Mac OS X 10.7.3. On 2/23/12 9:11 AM, Paul Topping wrote: > > I think you have touched the tip of an iceberg with your observations > here. Robert Miner and I had many discussions of problems like this. > Presentation MathML's domain of description tries to allow precise > formatting via specific dimensions and font and character choices as > well as logical description of math constructs. It always seemed to me > to be playing with fire. Left up to me, I would have had MathML > elements and attributes map to concepts in math's visual grammar in > order to allow the formatter to do a better job. Unfortunately, this > places a large burden on the author to get it right, something that is > a big problem for Content MathML. > > > > Paul > > > > *From:*mathjax-dev@googlegroups.com > [mailto:mathjax-dev@googlegroups.com] *On Behalf Of *Frédéric WANG > *Sent:* Thursday, February 23, 2012 1:02 AM > *To:* www-math@w3.org; mathjax-dev@googlegroups.com > *Subject:* [mathjax-dev] Embellished operators > > > > Hi all, > > I'm thinking again about the rules for embellished operators and it > seems to me that some elements are particular. For example if we ask > how to determine the stretching of something like: > > <math> > <mover> > <mo>→</mo> > <mtext>over</mtext> > </mover> > </math> > > The obvious answer is that the arrow should stretch to cover the over > script. OK. However one can also say that the <mover> is an > embellished element as a whole. Since is has no siblings, the arrow > should have its default size. > > To give slightly less trivial examples, what should be the size of the > arrows (100px or 200px?) in these examples: > > <math> > <mover> > <mspace width="100px"/> > <munder> > <mo>→</mo> > <mspace width="200px"/> > </munder> > </mover> > </math> > > and > > <math> > <mover> > <mspace width="200px"/> > <munder> > <mo>→</mo> > <mspace width="100px"/> > </munder> > </mover> > </math> > > An example with vertical stretching rules: > > <math> > <mrow> > <mspace height="50px" depth="50px"/> > <mrow> > <mo>|</mo> > <mspace height="100px" depth="100px"/> > </mrow> > </mrow> > </math> > > (I wonder if an attribute like embellishedop = "false" could help to > prevent this kind of ambiguity?) > > I noticed this because implementing the complete embellished op rules > caused a regression in Mozilla with MathML code generated by MathJax: > https://bugzilla.mozilla.org/show_bug.cgi?id=687807 >

Received on Thursday, 23 February 2012 19:42:41 UTC