
From:  Tim Daly 
Subject:  Re: [Axiomdeveloper] Semantic Latex 
Date:  Mon, 15 Aug 2016 08:39:35 0400 
On 8/14/2016 11:05 AM, James Davenport wrote:
Indeed, the semantics of LaTeX is pretty weak. I REALLY wouldn't like to start from there  even (good) MathMLP, with ⁢ etc. is much better.Face it: Mathematicians do it all the time. They read journal articles with
However, LaTeX is what we have, and what we are likely to have in the near future, so we must live with it, and yours seems like as good an accommodation as any.
no more information than the position of glyphs on a piece of paper.
There are poorly printed papers and reference books in which it is impossible
to be sure what the glyphs are (esp. books printed on crude paper in Moscow...)
And there are poorly written papers which cannot be read in isolation 
the authors (and reviewers, editors) have so much absorbed the context of
their field that they neglect to define their peculiar notation.
Nevertheless, that's what the literature looks like.
when I was trying to scan Gradshteyn & Rhyzik or similar books, we stumbled
over it page by page. I recall finding a place where we figured out what
the typeset integration result was by trying out our various
semantic opinions and differentiating.
Talking with runofthemill professional academic applied mathematicians is
sometimes revealing. At one demonstration (in Essen, Germany, a conference
on "Retrodigitalization" of mathematics  {It may sound better in German}, A
program of mine read in a page or two from Archiv der Mathematik, and spit
it out  but with a modern font, and in twocolumns, other changes too. The mathematicians in
the audience were thunderstruck, because they thought that the program must
have understood the mathematics to make that kind of transformation.
Of course all it did was guess at the
appropriate TeX to produce the equivalent spacing, and "knew" nothing of
the semantics.
Actually, I was amazed by the result when I saw it, but for two reasons.
(a) Someone else had actually used my program;
(b) There were no errors.
[The reason for (b) is that the recognition program had been trained on exactly
 maybe only  that page  it was trained so that defective/broken/linked characters were
mapped to the right answers].
But the point remains that if we wrote a program that was as smart as
(the collection of...) smartest human mathematicians, then TeX would be enough
semantics.
Another problem is that mathematicians do not mean what they write: $\frac{x+1}2$ is logically an element of Z(x), but the mathematician probably intended Q[x].I think that most people using DLMF.nist.gov would not know or care. It's not their part of mathematics.
It is probably unfortunate if Axiom (or Openmath or MathML) cares and consequently requires such users to know.
RJF
James
Sent from my iPhone
On 10 Aug 2016, at 11:50, "Tim Daly" <address@hidden> wrote:
There has been an effort in the past to extract mathematics from
latex. It seems that the usual latex markup does not carry enough
semantic information to disambiguate expressions.
Axiom has a similar problem occasionally where the interpreter
tries to guess and the compiler insists on type specifications.
Axiom provides an abbreviation for each type, such as FRAC for
Fraction and INT for Integer.
Might it be possible to create latex macros that take advantage
of this to provide unambiguous markup. For instance, instead of
\frac{3x+b}{2x}
we might have a latex markup of
\FRAC[\INT]{3x+b}{2x}
where there was a latex macro for each Axiom type. This would
turn into an latex \usepackage{AxiomType}
There would be a map from the \FRAC[\INT] form to the \frac
form which seems reasonably easy to do in latex. There would
be a parser that maps \FRAC[\INT] to the Axiom input syntax.
The problem would be to take the NIST Math Handbook sources
(is the latex available?) and decorate them with additional markup
so they could parse to valid Axiom input and valid latex input
(which they already are, but would validate the mapping back to
latex).
Comments?
Tim
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