Re: Similarity of Structure (was Memory Merging Possible for Close Duplicates)

From: Matt Mahoney (
Date: Mon Mar 17 2008 - 21:09:36 MDT

--- Mike Dougherty <> wrote:

> On Mon, Mar 17, 2008 at 7:45 PM, Lee Corbin <> wrote:
> >Suppose that by some *obvious* [1] isomorphism, today Lee is one bit
> string
> > 11011011001110010110111111001010110100000011...
> > and tomorrow I am
> > 11011011001110010110011111001010110100000010...
> >where two 0's happen to be changed to 1's. By all measures
> >of similarity, those two strings are still very similar. (It would be
> >easy to mention some particular measures used by mathematicians,
> >but the ones I'm completely familiar with without having to go look
> >them up aren't very applicable here.)
> Perhaps I did not find that isomorphism obvious enough. My initial
> confusion was related (i think) to the notion of your bit string in
> Platonia - which made no sense that it should be a different string
> from day to day. Now I realize that each byte position could be a
> measure of separate dimensions, some of which might be temporal - and
> that the string always represents a fixed point (Lee) measured from a
> moving observer.

Perhaps I am missing the point of this discussion, but the standard way to
measure the difference between two strings x and y is K(x|y) + K(y|x) where
K(x|y) is the length of the shortest program that inputs y and outputs x.

Also, what is the conceptual difficulty of having the memories of two people
who lived separate lives?

-- Matt Mahoney,

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