Re: compactness in angels/devil problem

On Fri, 1 Feb 2008 01:29:08 -0800 (PST), pauldepstein@xxxxxxx wrote:

The literature on the angels-and-devil problem often refers to a
"compactness argument" for passing from conclusions about finite
boards to conclusions about the infinite case. What is this
"compactness argument" and which topology is the compactness concept
being applied to?

What's the angels-and-devils problem?

Quite possibly the compactness being referred to is from
logic: If S is a collection of formulas and every finite subset
of S has a model then S has a model.

I could tell you what compact toplogy that's connected
with, at least in the case of propositional logic, but it
will take a little space. So first tell me what the d/a problem
is and what sort of assertions about the problem you're
talking about - the theorem I have in mind could be irrelevant.

Thank you,

Paul Epstein

David C. Ullrich
.

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