Arrow system

Billy Tanksley
Thu, 6 May 1999 13:20:23 -0700

> From:	Thomas M. Farrelly []
> Subject:	Re: Arrow system
> Imagine this. You have something describing the state transitions in an
> automata. Under TUNES it would be possible to do whatever you wished,
> and the lucky wish is: Put some system state invariants on the whole
> model, like "this and that state is to take maximum 1 second". So now,
> when going form one state to another, the system will sometimes test if
> the time spent in the last state is within a special interval. And if
> you wanted to, go to a special state depending on this.
> In the arrow system, you say that state transistions can be expressed
> simply by a graph of the transitions, but when you want to _add new
> information to it_, as it often the case in a reuse situation, it
> suddenly is no longer interpretable by the same ontology - and there
> need not be information available to create the new ontology from the
> old one. This means that it is not very easy at all to communicate the
> different graphs between the different ontologies that initially all
> talked about the same concept.
	Ah, but as I understand it, the purpose of the arrow system is to
allow you to _NOT_ have to modify the old code you're re-using -- instead,
you point to it from your new code.  The old code remains intact, ontology
and all.  Your new code doesn't modify it; instead, it "cuts into" the old
ontology and indicates the desired system.

	So you're not adding new information to old code, not really.

> It appears to me ( who is by no means an expert ) that you have
> reinvented the usefullness of references. But you lack real objects to
> reference. Surely you can call the definition of objects for ontologies,
> but it doesn't help much. It will not provide any uniform way of
> interpreting information. It's close to saying: "lets interpreted all
> information as bits!", "what about [fill in problem here] ?" - "I'll
> just use some more bits for that!" - and we all know how that went:)
> Flame me if I'm wrong, or give me a concrete example of how something
> real can be done. For example:
	I don't think you're wrong, honestly.  I wish I had some time to
work with this, but I don't.  So I have to reserve judgement, but in the
meantime I think this'll take a lot more work -- just like every other
comprehensive system of proof ever developed.  Riohgt now we don't even have
a proof system, only a simplistic modelling system.

	Have you read The Arrow Paper?

>     Thomas M.  Farrelly