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Re: [moca] Locations?

Martin Berger wrote:
> The question now is: isn't this just pi? where is the distribution?

for the sake of clarity, let me add that lsdpi enjoys the following law: if all the free channels of a process P are explicitly located (i.e. in the form a@s, being a the channel and s the location it belongs to), then s[P] ~ r[P]. thus, the behaviour of the process does not depend on where it is running.

so, we wounder if it would not be possible to have a fully abstract enconding of lsdpi into pi. notice that this should also be true for well typed dpi processes.

it would not be a bad thing if you could show your located calculus to
be expressible in some pi-calculus. designers of distributed systems
would love being able to mask distribution completely, alas they can't.


are we capturing the essence of a distributed system?

their problem is essentially that one cannot hide time and certain
types of failures. since your calculus features neither, it would not
be too surprising if distribution was not observable. on the other
hand carbone and maffeis (express'02) do get separation results
for what may be seen as a distributed pi-calculus, despite
the absence of time and failures. it also seems unlikely that the
full ambient calculus is syntactic sugar on top of some pi-calculus.

i don't think it is. neither i think that dpi is pi_2 (synchronising on pairs of channels).

this leads me to ask: exactly what feature separates locations (however
understood) from vanilla name passing interaction?

locations as collections of resources probably do not add much. it is like (flat) ambients with communication primitives but without open...

antonio

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