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Re: Fw: Making math equations accessible

From: Steven McCaffrey <smccaffr@MAIL.NYSED.GOV>
Date: Wed, 27 Nov 2002 08:39:16 -0500
Message-Id: <sde484c8.096@MAIL.NYSED.GOV>
To: <poehlman1@comcast.net>, <w3c-wai-ig@w3.org>

Hi all:
The rules are good and I think it is great that accessible equations has been given careful thought.
 
There is an error though in the example, y should be squared, (i.e. y^2) right?
Also the English is itself ambiguous.
The English itself should read
v equals the fraction whose numerator is 
the cube root of the quantity  x plus  the square of Y and whose denominator is Z."

As the English statement is written, one interpretation could be:
V equals [x^(1/3) + y^2] / z.

The word "quantity" is essential to eliminate this possibility by overriding precedence rules.

I think there's a file written by Abraham Nemeth on
writing and speaking mathematics unambiguously.
Using that notation would probably provide a better English-like statement than the one I used for the example.

Of course, if the mathematical expression was the only expression present, the issue of whether the English statement matched, or corresponded to, it would not come up but since both are given and do not unambiguously correspond, a reader wonders which was actually meant.
  

Steve



>>> David Poehlman <poehlman1@comcast.net> 11/26/02 05:48PM >>>


----- Original Message -----
From: "Alan Cantor" <Alan.Cantor@MBS.GOV.ON.CA>
To: <EASI@MAELSTROM.STJOHNS.EDU>
Sent: Tuesday, November 26, 2002 5:21 PM
Subject: Re: Making math equations accessible


Thank you to everyone who responded with their ideas. The approach we
have decided to adopt is to include an alt tag with each equation. The
equations themselves are images. The alt tags will follow these basic
rules:

1. Write equations linearly.

2. Use different levels of brackets to indicate different nested levels.

3. Use / for divide, * for multiply, ^ for exponent, etc.

4. Use commonsense expressions like sqrt for square root, Sum for sigma,
d(x) or dx for differential of x, etc.

Therefore, the alt tag for the equation V equals the cube root of x + y
squared, all divided by z, would be:

V = [ (x + y) ^ (1/3) ]  /z

Alan

Alan Cantor
Project Manager
Strategic e-Government Implementation
e-Government, OCCS
416-212-1152
Alan.Cantor@mbs.gov.on.ca 

>>> richj@ASU.EDU 11/26/02 04:34pm >>>
The question needs some clarification.  Do you have specific users that
need
to have access?  Are  you looking for a conversion process for math to
Braille or audio?  Or are you looking for a web based method of
presenting
math to anyone who clicks on the URL?

If it is the later, there are no complete answers.  MathML and LaTex
offers
several possible solutions.  Duxbury will convert some LaTex files. BUT
there is no standard for writing MathML or LaTex to create an accessible
files.
A completed conversion process is dependent on money, not ideas.

The short answer is that there is not an automatic way to do it.  The
most
usable (quick and dirty) method  of presenting symbolic information on
the
web is to use the same approach that is used with pdf files.  Have the
symbolic document in whatever, editor or graphic file you want and then
include a second accessible format.  An audio file of the symbolic
information would work. It would be nice if you also had the information
in
Nemeth Code, but unless you are expecting the users to compute the
information, audio would suffice.
Received on Wednesday, 27 November 2002 08:40:25 GMT

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