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Re: cancelling fractions

From: Neil Soiffer <NeilS@dessci.com>
Date: Thu, 31 Jul 2003 09:40:53 -0700
Message-ID: <026f01c35782$82d57ca0$6601a8c0@raindrops>
To: "Robert Miner" <RobertM@dessci.com>, <jpederse@wiley.com>
Cc: <www-math@w3.org>

----- Original Message ----- 
From: "Robert Miner" <RobertM@dessci.com>
To: <jpederse@wiley.com>
Cc: <www-math@w3.org>
Sent: Thursday, July 31, 2003 9:04 AM
Subject: Re: cancelling fractions


>
>
> Hi.
>
> > I have a related question: what is the correct way in MathML to tag
> > "crossed out" parts of fractions, used to indicate terms that have been
> > cancelled? If it is a single letter or number, then the combining
solidus
> > U+0338 would do the trick, but is there a way to indicate a line through
a
> > whole expression? Should I use
> > <mrow>...the expression...</mrow><mo>&#x0336;</mo> ?
>
> This won't work properly in MathPlayer.  I haven't tried Mozilla.

Doesn't work in Mozilla 1.4.

One problem with using solidus or other characters is that you don't have
control over vertical or horizontal positioning.

>
> My own preference would be to use the <menclose> construct.  I have
> long thought this is really the right way to do strikeouts, since it
> is more in line with the MathML philosophy of explicitly binding
> operators to expressions:
>
> <menclose notation="NESWslash">
>   <mrow> ... the expression ... </mrow>
> </menclose>
>
> I haven't thought about the right collection of values for the
> notation attribute, but you would obviously want NESW and NWSE
> slashes.
>
> If this is very important to you, I might be able to slip it into the
> current MathPlayer development cycle still.  I would be very
> interested to hear what the rest of the list thinks of this as well.
>
> --Robert

<menclose> or a new construct such as <moverstrike> would be the way to do
it if we were talking about an addition to MathML, but that is not an option
at the present.   Hence, I don't think your suggestion is a good one since
it means writing invalid MathML.  Perhaps a private namespace a new
attribute to menclose that would be understood by MathPlayer would be
better.

I don't think that there is any solution that will work with existing
browsers.  However, as Robert said, if it very important, I'm sure we can
come up with a legal solution that at least works in the next version of
MathPlayer.

Neil Soiffer                     email: neils@dessci.com
Senior Scientist                 phone: 562-433-0685
Design Science, Inc.             http://www.dessci.com
"How Science Communicates"
MathType, WebEQ, MathPlayer, Equation Editor, TeXaide
Received on Thursday, 31 July 2003 12:40:55 GMT

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