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From: Jack Uretsky <jlu@HEP.ANL.GOV>
Agreed.So an answer to your question is that there are?! How does this have to do with anything? Please explain.
only two "hands" because there are only two real roots of unity!
Let's go a step at a time. We need to agree on precisely what
you mean by "reverses". So consider a body to be a collection of points
in a space. Will you agree that "reverses" means an isometric (your word)
transformation on the collection that cannot be duplicated by a rotation
and/or a translation?
[snip]
mirrorNo. I actually asked, how aliens who had never seen a
rightwould explain both the difference and similarity between say, a
itand
left helix.Send the chemical formula for a substance with 2 isomers;
then keep sending your agreed symbol for the number "2".
Or (assuming they are super-intelligent) how would they, on
seeing an asymetrical object for the first time, would deduce that
askhad
Replied to by John Denker. By the alien analogy, I meant toone and only one counterpart (again lacking a mirror).
Since most objects are asymetrical, I don't understand
your question. There can only be one inversion in 3-space
because two co-ordinates determine a plane and the "handednedness"
of the co-ordinate system is determined by the orientation of
the 3rd co-ordinate.
objecthow intelligent beings would - on first chancing upon an asymetrical
familiarreason that it has a (only one) counterpart. Of course if they were
theywith a standard mirrors, or atleast the mathematical transformation,
wouldmight explain it way. But without the above, it seems to me that they
thefirst - by pure cerebration - discover the property of 'handedness' (in
Which is what I am trying to determine, in the first place? Justgeneral case- not just for that object or a class of objects). And myThis takes us back to your definition of "counterpart".
original question was - how?
replace 'counterpart' with enantiomorph. See the thought experiment with the
alien above.