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From: yodaiken@chelm.cs.umass.edu (victor yodaiken)
Newsgroups: comp.lang.misc
Subject: Re: Halting Problem Solved! Film at 11! (Was Re: definitions)
Message-ID: <30281@dime.cs.umass.edu>
Date: 8 May 91 23:54:51 GMT
References: <2861@optima.cs.arizona.edu>
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Reply-To: yodaiken@chelm.cs.umass.edu (victor yodaiken)
Organization: University of Massachusetts, Amherst
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In article <2861@optima.cs.arizona.edu> gudeman@cs.arizona.edu (David Gudeman) writes:
>Keep in mind that "state" in this sense refers to the entire body of
>information accessible by the computer.  If a computer runs out of
>storage, you can always go buy another tape.  Now there are two
>possible ways to interpret the question of whether this gives the
>computer unbounded storage: the practical and the theoretical.
>
>Whether this gives the computer _practical_ unbounded store depends on
>your opinion of what is practical.  If either you don't expect your
>problems to run out of tape, or your problems are important enough
>that you are willing to keep the computer supplied with all the tape
>it needs, then the computer has a practically unbounded state space.
>If you don't agree that the above is practical, then the computer has
>a _practically_ bounded state space.
>

Corret me if I'm wrong, but it seems as if proving that a program
will require at least the lifetime of the solar system to finish
computing on a device that switches in the time it takes an electron
to move 1 smallest measurable quanta, would be sufficient for most
practical purposes. 

>If you want to get theoretical, then you can _theoretically_ keep
>buying tapes until the world's supply of tape runs out.  Then you can

Of course, but now you are asking for a mathematical model which takes
your behavior into account. This is a rather more involved question than
the one we started with.