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Re: Unordered construct

From: <jeff@inf.ed.ac.uk>
Date: Mon, 11 Oct 2004 17:04:48 +0100
Message-ID: <1097510688.416aaf2004e6a@mail.inf.ed.ac.uk>
To: public-sws-ig@w3.org

Quoting Evren Sirin <evren@cs.umd.edu>:

> Description of Unordered construct in OWL-S 1.0 was closer to the first
> interpretation but for OWL-S 1.1 it is now being considered to adopt the
> second interpretation. There are couple of reasons for this change: 1)
> Sometimes it is more intuitive to think of composite processes as a
> single unit and it is required to put constraint on the composite
> process as a whole (as in the example Naveen pointed out) 2)
> Interleaving is already permitted in Split+Join and if interleaving
> between composite processes is allowed then in most cases concurrency
> between atomic processes can also be allowed.

I find the proposed change very counterintuitive.

"Unordered" sounds like a lack of constraints.  If anything,
it should even allow concurrency.  If we really want to change
the semantics, I think there should be a name change as well.
"Ordered"?  "Any-Order"?  "Permuted" :) ?

It looks like there are three cases:

  1. Concurrency (and hence interleaving) is allowed.
  2. Interleaving is allowed, but not concurrency.
  3. Neither is allowed.

Right now, we lack (3), and the proposal is to change so that
we instead lack (2).  Is that right?

At the moment, perhaps it seems (to some?) that (3) is more
important than (2), but how do we know that won't change?
It all seems messy to me, without a clear rationale.

(I don't, by the way, think it's "clear that Unordered *should*
imply non-concurrency" [emphasis added].)

-- Jeff
Received on Monday, 11 October 2004 16:04:49 GMT

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