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

From: Steve Ross-Talbot <steve@pi4tech.com>
Date: Tue, 17 Jan 2006 11:55:06 +0000
Message-Id: <9dfff906b27eeeddcc46068534fb6ba8@pi4tech.com>
Cc: <public-ws-chor@w3.org>
To: "Paul Bouche \(HPI\)" <paul.bouche@hpi.uni-potsdam.de>

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  

What is it that you are trying to do with respect to WS-CDL?


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 11:55:22 UTC

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