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Re: WS-CDL and (polyadic) Pi-Calculus

From: Paul Bouche \(HPI\) <paul.bouche@hpi.uni-potsdam.de>
Date: Tue, 17 Jan 2006 13:02:15 +0100
Message-ID: <43CCDCC7.5070407@hpi.uni-potsdam.de>
To: "Steve Ross-Talbot" <steve@pi4tech.com>
Cc: <public-ws-chor@w3.org>

Hi Steve,

I am trying to answer the initial question "Is WS-CDL 'based' on 
Pi-Calculus?" within the context of the aforementioned seminar at my 
university. I will hold the talk tomorrow. If you are interested I could 
I email you my slides or anyone else who expressed interest, yet I would 
not be comfortable sending it to the public list.
In answering that question I am trying to analyze the concrete 
relationship of WS-CDL and Pi, ie what concepts in WS-CDL come from Pi.

Thx,
Paul

Steve Ross-Talbot wrote:

> Hi Paul,
>
> I am referring to [3] when talking about formal treatments. [1] was 
> an  early thought about how to do it and has given rise to [3]. 
> Whereas [2]  is Nick's partial treatment which is now subsumed by [3] 
> and what will  follow in Q22006 (Quarter 2 2006).
>
> You are correct that workunits are not influenced by pi-calculus. 
> They  are more data-flow influenced. But they are representable in pi 
> and  have a formal treatment in GC and through to the EPC. And yes pi 
> is not  typed as such, although there is the notion of sorts which is 
> much the  same.
>
> What is it that you are trying to do with respect to WS-CDL?
>
> Cheers
>
> Steve T
>
> On 17 Jan 2006, at 11:32, Paul Bouche ((HPI)) wrote:
>
>> Hi,
>>
>> thanks Ingo and Steve for your answers.
>>
>> The IMHO goes for all I am about to say.
>>
>> Ingo, channels and sending of channels, I clearly see as inspired 
>> from  Pi, but the work unit concept, all the concepts finalizer, 
>> exception,  roleType, participantType, bahaviour and state mangement 
>> concepts I  don't see how the were inspired from Pi. Those are added 
>> and more  high-level than Pi. The grouping concepts for activities 
>> are clearly  those of Pi: Seqeunce, Parallel, Choice. Yet there is a  
>> while-loop-grouping construct which is also not found in Pi. Surely  
>> all these concepts can be expressed with Pi-Calculus with more or 
>> less  effort. The exchange interaction concepts also is clearly 
>> inspired by  Pi. Pi does not differentiate between variables, 
>> channelTypes,  channelType instances, names of channels, tokens etc. 
>> This is another  high-level addition. Also from my knowledge 
>> Pi-Calculus is not typed  at all, it does not even have a data flow 
>> centric concept but it is  all process centric or oriented.  This 
>> orientation I cannot clearly  see in WS-CDL. Yet this may also not be 
>> possible because of the goals  for WS-CDL, and also because of that 
>> high-level constructs had to be  added.
>>
>> Steve are you refering to [1], [2] and [3] when you talk about 
>> "Global  Calculus"? What does "Q22006" mean - 12/22/2006 - which 
>> would be  December 12th 2006?
>>
>> Thank you for you inputs!
>> Paul
>>
>> [1] Carbone, Honda, Yoshida, "Programming interaction with Types" ,   
>> http://www.w3.org/2002/ws/chor/5/06/F2FJune14.pdf
>>
>> [2] Kavantzas, "Aggregating Web Service: Choreography and WS-CDL",  
>> http://lists.w3.org/Archives/Public/www-archive/2004Aug/att-0017/WS- 
>> CDL-April2004.ppt
>>
>> [3] Honda, Yoshida, et. al. "A Theoretical Basis of  
>> Communication-Centred Concurrent Programming",  
>> http://lists.w3.org/Archives/Public/public-ws-chor/2005Nov/att-0015/ 
>> part1_Nov25.pdf
>>
>> Steve Ross-Talbot wrote:
>>
>>> Deal Paul,
>>>
>>> Yes the channels where inspired by pi-calculus. They are a channel 
>>> or  port pairing. The work of our invited experts looks at providing 
>>> a  new calculus called CG (Global Calculus). When we project  
>>> participants we do so to an EPC (End Point Calculus) which is  
>>> pi-calculus with session types. The session information comes from  
>>> the identity tokens described as part of a channel type. This EPC 
>>> is  what we use to enforce liveness and other relevant properties  
>>> (bi-simulation etc).
>>>
>>> The plan is to publish the finished treatment of GC and EPC 
>>> sometime  in Q22006 as a working note.
>>>
>>> Hope this helps
>>>
>>> Steve T
>>
>>
>>
>>
>
Received on Tuesday, 17 January 2006 12:02:35 GMT

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