[Om3] Being pragmatic about the semantics of, eg, variables and functions

[David Carlisle]

> Hence I want all 'bindings' in OM to require a 'condition on the bound
> variables'.  Syntactically this can, perhaps, be omitted but with an
> assumed default value.

[I cut out cc to member-math as it's a closed list]

It's perfectly reasonably (but a big change) to want to base things on a
typed (or conditioned) system rather than an untyped one. (Not sure that
OM could survive the surgery required, but it's certainly something that
could be considered).

But that seems a more or less completely separate issue from
James/Michael's proposal, which doesn't add a distinguished syntactic
component to OMBind for conditions (such as the once proposed OMC element)
but rather just adds an open ended list of expression terms to be
included in the binding, which may (on a symbol-by-symbol basis) be
taken to be conditions on the bound variable, or constituent subterms
of the expression being bound or anything else.

In MathML terms what you are saying is that you'd prefer that the
specification insisted that every <bind> had a <condition> child that
constrained the variables. What the proposal at the start of this thread
suggests is that every <bind> may have an arbirtrary number of children
(after the qualifiers) rather than just one. One of these propsals is a
change, but to a well understood (if different) mathematical formulism,
the other is a change to a novel syntactic construct that seems to be at
best loosely defined, namely a binder that is simultaneously binding
multiple, but otherwise unconnected terms.

David

________________________________________________________________________
The Numerical Algorithms Group Ltd is a company registered in England
and Wales with company number 1249803. The registered office is:
Wilkinson House, Jordan Hill Road, Oxford OX2 8DR, United Kingdom.

This e-mail has been scanned for all viruses by Star. The service is
powered by MessageLabs. 
________________________________________________________________________