[Prev][Next][Index][Thread]

Re: on goals



At 11:29 PM 6/17/96, Ka-Ping Yee wrote:
>> Renderings in speech need to convey more than a "2D picture" of the
>> expression.
>
>I definitely agree with what Raman says here.
>
>That document at [GENERAL] makes many references to a "2-D
>presentational structure" and a "2-dimensional form of an expression".
>I believe this is *not* what a mathematical or structured-expression
>notation should be based upon, and i disagree with this statement as
>as a design goal [DESIGN].
>
>A two-dimensional model is too limiting and presentation-specific.
>The goal should be a language that conveys the semantics and structure
>of an expression.


Welcome to the group!

Some of the documents you refer to are obsolete. For the current
state of the proposal from Wolfram, see my letter to the list from
31 May 96, which supersedes everything before it.

As for the issue mentioned above, I also agree with Raman's later
comments (on a conference call). I think this was mainly a
misunderstanding. I meant to refer not to 2-dimensionality itself, but
to the abstract structure of the notation, as opposed on the one hand
to the precise but low-level 2-dimensional layout (nothing except
absolute sizes and positions of symbols), and on the other hand to the
purely semantic structure of what some notation is conventionally
understood to mean (but by a complex and incomplete and
not-standardized correspondence of structure to meaning).

The reason I nonetheless used the terminology "2-dimensional" is because
an essential part of this abstract structure is that there are several
choices of "relative size and position" for the subexpressions of an
expression, which often convey different meanings (e.g. the subscript
and superscript positions). Though these are (in principle) abstract
logical relationships independent of the 2-dimensional form, there is
no standard terminology for them (in general) except that which refers
to the 2-dimensional form.

I agree that the language I chose led to confusion about this, and
should be improved. Raman was going to suggest a rewording of that
paragraph, but I don't think he ever did so. When writing it I found it
pretty hard to come up with a short phrase that expressed what I meant.
Perhaps "abstract notational structure" is best?