- From: Neil Soiffer <NeilS@dessci.com>
- Date: Mon, 7 Oct 2013 15:37:03 -0700
- To: Neil Soiffer <NeilS@dessci.com>
- Cc: Frédéric WANG <fred.wang@free.fr>, mathjax-dev@googlegroups.com, "www-math@w3.org" <www-math@w3.org>
- Message-ID: <CAESRWkCfzbfe-6rWwH4iMgfax9f-VKtG_Qo330pDPcNSWsLeYw@mail.gmail.com>

I didn't hear any objections or even anyone point out that "northwestarrow" should have been "north*east*arrow" (I'm pretty embarrassed by that mistake!). The draft-spec has been updated with that fix: http://www.w3.org/Math/draft-spec/chapter3.html#id.3.3.9.2. Neil Soiffer SeniorScientist Design Science, Inc. www.dessci.com ~ Makers of MathType, MathFlow, MathPlayer, MathDaisy, Equation Editor ~ On Mon, Sep 30, 2013 at 1:49 PM, Neil Soiffer <NeilS@dessci.com> wrote: > I apologize so much time has elapsed, but the working group took a long > time to come to some consensus. The two main issues that we needed to > resolve were mirroring (bidi) and naming that can be extended. > > It's clear that for the \cancelto notation, the symbol should mirror. > However, the diagonalstrikes don't mirror, and it's not clear that once > extended to all possible (single line) arrows, that all the arrows should > mirror. Furthermore, if someone is authoring in a RTL language, it is > highly likely the characters they use will come from that language so at > least the cdata of the leaves in the MathML would need to change. Requiring > the author to also change to an menclose attr value is not a big deal if > they want their example to work for an LTR language. In the end, the group > felt we shouldn't change the spec for how "updiagonalstrike" and > "downdiagonalstrike" behave and that arrow notations should not flip in an > RTL context. > > For naming, we considered lots of alternatives and concluded there was > some precedence with unicode naming and with TeX naming that compass points > along with up/down/left/right were used. So *if* a full set of names were > to be used, they should follow the conventions: > > uparrow > rightarrow > downarrow > leftarrow > > northwestarrow > southwestarrow > southeastarrow > northeastarrow > > updownarrow > leftrightarrow > northwestsoutheastarrow > northeastsouthwestarrow > > That means for the cancelto notation, the name should be > "northwestarrow". Given that mathjax and mozilla support a different name, > I suggest just adding this new alternative to accepted names. > > The spec mentions the naming convention, but only lists "northwestarrow" > as a recommended name to support. > > The draft-spec is at: > http://www.w3.org/Math/draft-spec/chapter3.html#id.3.3.9.2. > > Any comments? > > Neil Soiffer > SeniorScientist > > Design Science, Inc. > www.dessci.com > ~ Makers of MathType, MathFlow, MathPlayer, MathDaisy, Equation Editor ~ > > > > > On Mon, Sep 9, 2013 at 12:27 AM, Frédéric WANG <fred.wang@free.fr> wrote: > >> I am the one who proposed this notation, so perhaps I should say a word >> on this. >> >> First, as I said I've never seen this notation in France so I can't >> comment about its usefulness other than believing you that it is (or was) >> used at least in K12 math in the US. It's probably not fundamental to have >> this notation (even the doc of the cancelto says that striking formulas is >> a poor notation), but at least it was implemented independently in two >> different projects (LaTeXML and MathJax) with essentially the same method: >> menclose updiagonalstrike + a superscript element. So it was important >> enough to need an implementation and the MathML code to choose seems >> somewhat natural since the two developers had the same idea. I don't like >> that menclose notation names don't take the overall direction into account >> but here that seemed irrelevant if, as I believe, it's not used in RTL math >> (the W3C Arabic Math notes doesn't mention it). So I thought it was OK to >> add one menclose notation for this particular arrow, but I definitely don't >> see the need for other striking arrows if there is no use case. >> >> The reason why I proposed this notation is that MathJax used to have a >> non-standard class on the menclose element: >> >> <menclose notation="updiagonalstrike" class="MJX-arrow">...</menclose> >> >> to tell that the updiagonalstrike should have an arrow head. Hence >> MathJax rendered the notation visually the same as the cancelto command but >> other rendering engines like MathPlayer or Gecko just renders an >> updiagonalstrike. Moreover, other TeX to MathML converter like LaTeXML are >> not aware of MathJax's non-standard CSS classes and can not achieve the >> same rendering via standard MathML (for example Bruce only used an >> updiagonalstrike). Obviously, I don't like these specific hacks in MathJax >> and I hope these nonstandard MJX-* classes will be implemented via standard >> means in the future. In the case of cancelto, the menclose notation is >> open-ended so I thought it would be easy to add a new notation for that. >> Now MathJax and LaTeXML uses >> >> <menclose notation="updiagonalstrike updiagonalarrow">...</menclose> >> >> and this will be supported by Gecko 24 (to be released next week). I'd >> like this to be in MathPlayer too, but even if that's not the case, >> MathPlayer will just render the notation "updiagonalstrike" as it has >> always done, which is understandable... >> >> Le 08/09/2013 20:24, Neil Soiffer a écrit : >> >> The fact that it was one of the most requested features for MathJax is a >> strong argument for adding it to MathML. I still remain dubious about its >> use though. My kids have gone through/are going through K12 math and I've >> never seen arrows used as part of crossouts in any of the books or online >> materials they used/we've looked at, either for cancellations or for >> carries/borrows. But that's just anecdotal evidence which is why I was >> hoping that Bruce Miller or Michael Kohlhase could give some input as to >> usage based on their arXiv work since they will see the macro and will have >> needed to implement it (or not) for LaTeX2XML. >> >> You also touched on a hot button topic for me: I'm strongly against the >> idea that hacking solutions with mpadded or playing games with tables to >> achieve a particular presentation is acceptable. It means the result is not >> accessible and a certain percentage of the population is excluded from >> using the material. I'm not arguing for semantic usages, I'm just arguing >> that the presentation be able to be audibly described to the user in a >> meaningful manner. E.g,. 'x minus 1' with a horizontal strike across it" >> is understandable and but not semantic. However, playing games with mover >> and mpadded: "x minus 1 with a line above it that has a negative depth of >> 15 pixels" is gibberish and if the mpadded is not spoken, (... with a line >> above it), the result is very misleading. >> >> Neil >> >> >> >> On Saturday, September 7, 2013 8:46:36 AM UTC-7, dpvc wrote: >> >>> > The original use for the notation pointed to the TeX package that >>> implemented "cancelto". But this command has another argument which the >>> arrow points to. That doesn't fit into the menclose notation. >>> > >>> > As you can see, I'm rather skeptical that adding this is a good idea. >>> Perhaps Bruce or Michael can look at arXiv files and tell us how many >>> times cancelto is used in those files. Maybe it is much more common than I >>> think it is. >>> >>> Before the cancel package was added to MathJax, it was one of the most >>> requested extensions that we had. It is used frequently at the K-12 level, >>> but not so much in higher level mathematics, so I would be surprised if >>> arXiv showed much use of it. You would need to look at educational >>> material rather than research papers. >>> >>> While I understand your desire for symmetry in providing all possible >>> arrows, I don't see the mathematical need for anything but the lower-left >>> to upper-right arrow, as I am not aware of any other usage. There >>> certainly may be, but they would be far less prevalent than this. And to >>> propose a lot of additional notations for which there are no ready use >>> cases, and then use that to suggest that the one notation that DOES have >>> use cases should not be implemented seems a bit backhanded to me. >>> >>> As for those other notations, I would say that vertical and horizontal >>> arrow notations are not needed because there are already means of obtaining >>> those arrows (even stretched to the proper sizes, and they can be placed >>> above or below with mover or munder, to the left and right via >>> juxtaposition, and struck through vertically or horizontally with mpadded), >>> while there is no mechanism for obtaining diagonal arrows at arbitrary >>> sizes. If you want to say that you need such arrows in all directions, and >>> with one or two arrowheads because they would be useful in commutative >>> diagrams, then I could see that (though it would be awkward to use menclose >>> for that), and this would lead to 6 new notations (or 4 if you just to the >>> heads separately); but suggesting that the need for a cancelation arrow >>> necessitates 23 other arrows seems to me to be taking the desire for >>> symmetry too far. >>> >>> Davide >> >> -- >> You received this message because you are subscribed to the Google Groups >> "MathJax Development" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to mathjax-dev+unsubscribe@googlegroups.com. >> For more options, visit https://groups.google.com/groups/opt_out. >> >> >> >

Received on Monday, 7 October 2013 22:37:32 UTC