- From: <juanrgonzaleza@canonicalscience.com>
- Date: Fri, 19 May 2006 11:20:05 -0700 (PDT)
- To: <www-math@w3.org>
- Cc: <lroffey1@ix.netcom.com>

Leane Roffey wrote: > You write: A possibility for elimination of brackets is working only > 2-ary operators > in postfix form. The code (a kind of infix LISP): > > [Y \= [plus [times a \* x] \+ b]] Sorry it would be [Y = [[a * x] + b]] > can be expressed in a FORTH-like way > > a x * b + Y = > > But last expression is less readable than Lot of Irritant Silly > Parentheses ;-) > ***** > > I've worked with FORTH (back when the earth was cooling). Is that when Ace Age I movie? ;-) > Less readable, perhaps, but if you were a FORTH user, they > were a breath of fresh air. I mean less readable for 80-90% people. How many RPN calculators do you know ? 2%? > I think you have a point here worth looking > at. (perhaps issued from the Bureau of Silly Random Walks :-) ) > Those work for simple expressions, there is no doubt. > > The whole question of "greenfield" issues, like encoding > negative numbers often involves the assignment of multiple uses > to the same physical character. As I've seen before on this > forum, sometimes that's important to clarify, and other times it isn't. > > I recently consulted for a nationally known tutoring center as a > mathematics specialist, and in examining the arithmetic for > grades K-12, found that for some time now, the children are > shown negative integers as the integer with a superscripted > "minus sign" either in front or back of the number. It varied > by textbook. > > When presented then, with expressions like "some positive > number minus some negative number" or "some negative > number minus some negative number" the resulting confusion > was the stuff of legend. This concerned me because the > ultimate goal of content MathML, in my applications, would be to be able > to present interactive learning to any audience, integrating > both correct representation of intent by the user and ensuring the > answer would be correctly interpreted by any scripting compiler > running the page by any browser anywhere. Richard has > already pointed out the issues about browsers. What issues? > Documentation, > for which both style and content would be important, for me, is > vital. Short of representing any negative integer by the mirror > image of its positive integer around zero, I can't think of any > way around this difficulty offhand. - 1 = 0 - 1 "some positive number minus some negative number" a - (- b) a - (0 - b) "some negative number minus some negative number" -a - (- b) (0 - a) - (0 - b) > Your points on compilers are well-taken. They are tricky devils, > depending on the language and how run-time oriented they are. > I could wax for hours on the differences, but that would really > be off topic for this thread. > > Leane > > Leane Roffey Line, Ph.D. > Research Engineer > www.bioelektronika.com > Neuro Magnetic Systems > San Antonio, TX 78209 Juan R. Center for CANONICAL |SCIENCE)

Received on Friday, 19 May 2006 18:20:23 UTC