Re: comments re draft version 2.0

My last message was predicated on the previous round in which it
was indicated that "D" was formally typed as "operator" (under an
oversimplified type description),  "y" was formally typed as
"function", and the typing system enables the robot to understand
that operators act on functions.

> (aside:  this double use of notation is a difficult point for many weaker
> students as well,  perhaps because they  too have too little context.)

Of course, I know this well.  In fact, the challenge for the student
is very similar to that faced by the robot: figuring out how to parse
mathematical notation correctly by figuring out exactly "where" each
subexpression in the parse "sits".

My fundamental point is that proper typing is *all* that is needed
beyond traditional notation for author markup that can be translated
to content MathML.  And the types can (and should) be relative.

                                     -- Bill