[cap-talk] Partial authority

[David Hopwood]

David Hopwood wrote:
[...]
> The definition above says that both alice and bob [*] have (partial) authority
> to cause the message to be sent to ted. Let's work through it:
> 
> If s is the sequence
> <alice sends carol <- shakeLeftHand(), bob sends carol <- shakeRightHand()>
> and e is "carol sends ted <- run()",
> 
> then removing "alice sends carol <- shakeLeftHand()" from s to give
> s'_a = <bob sends carol <- shakeRightHand()>, we see that e cannot follow s'_a
> 
> and removing "alice sends carol <- shakeLeftHand()" from s to give
> s'_b = <bob sends carol <- shakeRightHand()>, we see that e cannot follow s'_b.

Sorry, cut-and-paste error (the conclusion is unchanged).

  and removing "bob sends carol <- shakeLeftHand()" from s to give
  s'_b = <alice sends carol <- shakeRightHand()>, we see that e cannot follow s'_b.

> I.e. the definition says that both alice and bob are involved in the causal
> chain that leads to run() being sent to ted.

The second example was correct.

-- 
David Hopwood <david.hopwood at industrial-designers.co.uk> (note new address)