Re: Questions about theory assingment

Bob Walton (walton@deas.harvard.edu)
Fri, 7 Apr 2000 08:30:55 -0400 (EDT)

..1.)In Lemma 9 we are supposed to use the notation as in Definition 8. Does
..this mean that we can assume:
..a.)e_1 in E with an initial segment e' and last transtion t
..
..b.)e_2 in E is a continuation of e' such that all the transitions in e_2-e'
..are internal, the first trasition or e_2-e is failed(t) and
..projection_i(e_2-e')=projection_i(e_1-e')
..
Yep; for some i = 1 or 2; actually i= sender(t)

..With this assumptions the proof looks simpler and I'm worried that I could
..be making the wrong assumptions.
..
You can assume these. Actually, you do not need to assume some of it.
The lemma uses only a smallish subset of available information.

..2.)In Lemma 12 shouldn't we assume that e_1 and e_2 share an initial segment
..e'?
..
Intuitively no. But remember the empty path from any state to itself
is an execution.

..3.)Proof by using contradiction would be a good strategy?
..
..
You mean for Theorem 13. Yes.

BW