Re: [FWP] japhy had a silly idea...

[Marc Lehmann <pcg@goof.com>]

On Mon, May 28, 2001 at 07:17:33PM -0400, Ronald J Kimball <rjk@linguist.thayer.dartmouth.edu> wrote:
> I don't follow you.  Integers are obviously countable:
> 
> 0, 1, -1, 2, -2, 3, -3, 4, -4, ...

so are the strings a regex can match.

> said, the set of reals between 0 and 1 must be countable, because each real
> can be represented as a string, specifically a string of digits.

the point is complexity. try to give a mapping of reals to strinsg and
you will find it's not as easy as you think. you will always end up with
an algorithm which cannot be proven to terminate. that's why I meant with
"there is no *obvious* mapping". the problem is that abigail concludes
that a regex might match all these infinite strings.

however, regexes (at least the regular ones, not the perly ones) don't
have this problem.

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