[cap-talk] Is "Authority" Subjective?

[Jonathan S. Shapiro]

On Fri, 2007-06-22 at 15:48 +0100, Toby Murray wrote:

> I think my original example was misleading. let me present the same
> example but with concrete event names to try to show a clearer picture
> of what I mean here.
> 
> Suppose we have 3 objects/subjects/actors/whatever, Alice, Bob and Carol
> and the system is 
> 
> P = aliceInvokesCarol -> carolRespondsToAlice -> bobInvokesCarol -> STOP
> []
>     bobInvokesCarol -> STOP
> 
> i.e. initially either Alice or Bob can invoke Carol. Once invoked by
> Alice, Bob can't invoke Carol until she responds to Alice. 

This may be getting closer, but this is still insufficient. This model
states what events occurred, but it makes no statements about what
permissions were required as a precondition for those events.

Further, this model doesn't have any notion of a system "state" that is
being updated. If you want to model authority, the interesting issue is
not whether the event occurred, but what the effect on the system state
was. Also, it is not important *who* performed the event. It is
important what event occurred.

In effect, what you are describing above is a particular sequence of
operations that was performed by some underlying operational semantics.
What you *want* to be describing is the operational semantics and the
system state that defines the meaning of these events.


shap