[Om3] Pragmatics, timing, summary, and proposed resolutions

[Robert Miner]

Hi.

I think I end up with basically the same plan of action as Michael.
Here is how I think through it:

The plan we've been working on is that pragmatic markup continues more
or less as it always has, but that the spec would define its semantics
by providing a normative mapping to a "strict subset" instead of an
idiosyncratic (and wrong and inconsistent, etc) appendix.  The strict
subset alone isn't sufficient, since it doesn't itself define the
semantics of its symbols.  So we were going to ground it by pointing to
OM CDs for those definitions.

At the time we made that decision, the idea was to point to OM3, not
OM2, where OM3 would be free to change in response to what was needed to
better push through the above program, and would be done before MML3.
Obviously, this hasn't happened, and I think people are generally
acknowledging that the timing constraints are such that is can't happen
anymore.  Consequently, there isn't really any room for debate on the
basic point that MML3 is stuck referencing OM2.  

Now, it was also a goal that strict markup be structurally isomorphic to
OM3.  Note, however, this is not a requirement for pushing through the
above program.  It doesn't even have to be structurally isomorphic to
OM2, so long as it is logically sound.  The problem we are facing is
that it can a) be isomorphic to OM2, b) try to be isomorphic to OM3, c)
be loosely defined so it can be isomorphic to either.

Given the lively debate over OM3, I don't think b is likely to succeed
on the compulsory timeline that confronts us, even if we all agree it is
what we want (which we don't).  That leaves a or c.  

Where Michael ended up in his email (my interpretation) is that we have
to proceed on the basis of a), and if the OM3 debate progresses fast
enough try our best to switch to c) at the last minute if there is time.
We probably differ on the details of what "switching to c at the last
minute means" -- with Michael hoping to actually have time to change
some of the details of the P2ST transform, and my thinking we will be
lucky if we can manage to open up the schema enough to at least allow
strict markup to be isomorphic to OM3.  But that can await events, and
once the timing and content of OM3 is clearer, that question should
answer itself.

--Robert






> -----Original Message-----
> From: member-math-request at w3.org [mailto:member-math-request at w3.org]
On
> Behalf Of Professor James Davenport
> Sent: Wednesday, March 25, 2009 7:00 AM
> To: David Carlisle
> Cc: jhd at cs.bath.ac.uk; om3 at openmath.org; member-math at w3.org
> Subject: Re: [Om3] Being pragmatic about the semantics of, eg,
> variables and functions
> 
> 
> On Tue, March 24, 2009 10:04 pm, David Carlisle wrote:
> >
> >> That's not quite the same thing (fortunately). If Chapter 4 is
> merely A
> >> translation Prag->S (which is what I would hope) then evolving OM
> will
> >> let
> >> us improve a "best efforts" translation, which would be a nice
> position
> >> to be in.
> >
> > it's not just _a_ translation. In MathML 1 and 2 the meaning of the
> > content markup was given in a CD-like appendix using a notation and
> > prose style that was unique to mathml. Under that model, there is
> scope
> > for any number of "best effort" conversions from MML to OM.
> >
> > In MathML3 the meaning of the content markup is defined by its
> > translation to strict. So (unless there is an error in the spec,
> which
> > happens of course) an alternative, later, translation to strict
> mathml
> > must produce something that is mathematically equivalent, as the
> element
> > is defined by the specified translation.
> Understood, and apologies if that wasn't clear. But there might be
> pragmatic markup whose meaning wasn't defined, or where we can think,
> maybe as CDs evolve, of "better", but still mathematically equivalent,
> OM.
> >> Which essentially means, as I understand it, that 'condition' is
> either
> >> IN or OUT, irrespective of CDs.
> I meant, "in strict", sorry.
> > yes but of course it doesn't have to mean anything. You can
construct
> > all kinds of expressions that don't have any obvious semantic
> >
> > <apply><cn>1</cn><condition><pi/></condition><cn>2</cn></apply>
> >
> > is valid mathml which perhaps means the function 1 applied to 2,
> But as I understand it, the P->S would fail to convert this. Am I
wrong
> here? This is a key illustration.
> [I'll come back to the rest later]
> 
> James Davenport
> Visiting Full Professor, University of Waterloo
> Otherwise:
> Hebron & Medlock Professor of Information Technology and
> Chairman, Powerful Computing WP, University of Bath
> OpenMath Content Dictionary Editor and Programme Chair, OpenMath 2009
> IMU Committee on Electronic Information and Communication
>