Re: MathML and ImaginaryJ

Dear Scott,

There is yet another possible way that a content tag representing
ImaginaryI might be renderable as a "j", namely, using a renderer
which has support for user modification of its rendering rules
for content tags. (Two of Robert's answers address the possibility
of author modification of the rendering rules, as opposed to user
modification of them; either or both of these possibilities might
be desirable.)

This would allow you as a reader to configure your MathML renderer
to show all content tags representing ImaginaryI as "j", regardless
of whether the author had intended that.

MathML renderers are free to make this possible in any manner
(not necessarily waiting for XSL style sheets), and indeed are
encouraged to make it possible, though we can't predict how many
of them will do so.

- Bruce Smith
HTML-Math WG member

At 1:32 PM 1/12/98, rminer@geom.umn.edu wrote:
>Dear Scott,
>You wrote:
>> Is there expected to be support for replacing/overloading the
>> presentation types for the content objects?  
>> i.e., can "ImaginaryI" be presented as "j" 
>> -- I'm a EE and we all use "j" for Sqrt[-1]
>We do expect support for selecting between various presentations of
>content objects like "ImaginaryI".  In fact there are several escape
>One way would be to simply bind a different presentation to
>a content object using a <semantics> element.  However, until there
>are macros, this is a real pain. 
>Similarly, ultimately, we are expecting MathML to be rendered natively
>in browsers using XSL style sheets, which is really the right way to
>do this.  However, that is also some years off.
>A more immediate, but also implementation specific, work around is the
>"other" attribute.  This is meant to provide implementors with a place
>to put implementation specific flags like "engineering_style" or
>whatever, that would tell a renderer to use j for &ImaginaryI;.  In
>the draft (buried in section we use the example of switching
>between dots and primes for derivatives, and the i/j thing is similar.
>I hope this is a satisfactory answer.
>Robert Miner
>Robert Miner                               http://www.geom.umn.edu
>The Geometry Center                        phone: (612) 626-8313
>HTML-Math WG co-chair                      fax:   (612) 625-8083