Re: the semantics of deckchairs

[A E Lawrence <A.E.Lawrence@xxxxxxxxxxx>]

On Mon, 2003-03-17 at 11:41, Jim Davies wrote:
> 
>    I am not sure who said that and in what context. 
> 
> Probably me. 
> 
>    That is all about the semantics of hiding and offered events not
>    actually accepted (in my denotational terminology). The point is
>    that a CSP(P) process can undergo internal transitions as a result
>    of an offer, even if the offer is not accepted.
> 
> Sounds like a move towards a refusal testing model.  Hmm.  It also
> sounds like people spending a lot of time trying to (re-)invent useful
> variations of the failures representation.
> 
> And, in the process, missing the point entirely.

Jim,

As far as I know, and please tell me if I am wrong, there is no
satisfactory way of capturing

1) priority
and 
2) infinite behaviour 

in failures. I don't regard a model which is not a CPO with respect to
refinement to be satisfactory.

Overtures and hesitant offers are just  a small excursion within that
approach.  If you have real objections to Acceptance semantics which
explains why it is not substantially superior to Failures, please tell
me. Probably off list.

Adrian


> 
> I don't have time to give a one-week course on the subject in email
> form.  (Although I might be able to arrange a substantial discount if
> you wanted to attend one.)
> 
>    In almost all realistic circumstances, "overtures" should be
>    included. 
> 
> This is complete nonsense.  ;^).  Sorry, but it really is.  
> 
> In arriving at an adequate representation, you may need to consider
> whether unsuccessful (in some sense) attempts at communication should
> be recorded.  

This is the way "eagerness" of hidden events is captured, and throws
light on that eagerness. Otherwise, we don't get standard CSP hiding.
But as I haven't defined or explained overtures in my sense, we may be
at cross purposes