W3C home > Mailing lists > Public > www-rdf-interest@w3.org > January 2002

RE: what RDF is not (was ...)

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Fri, 04 Jan 2002 11:48:58 -0500
To: m.batsis@bsnet.gr
Cc: www-rdf-interest@w3.org
Message-Id: <20020104114858Q.pfps@research.bell-labs.com>
From: "Manos Batsis" <m.batsis@bsnet.gr>
Subject: RE: what RDF is not (was ...)
Date: Fri, 4 Jan 2002 18:10:55 +0200

> 
> 
> > -----Original Message-----
> > From: Peter F. Patel-Schneider [mailto:pfps@research.bell-labs.com] 
> 
> > The nth element of the fractional part will be 
> > 1 if U(n) is a URI that represents a real number that has the 
> > nth element
> >   of the fractional part of its decimal expansion anything but 1
> > 2 otherwise
> > 
> 
> My apologies but I don't seem to get the obvious, this specific part
> ruins it all for me. BTW, is the length of the fractional part finite as
> well along with the Unicode char sequence?
> 
> Kindest regards,
> 
> Manos

What is not obvious about it?    All real numbers between 0 and 1 can be
represented as infinite sequences of decimal digits.  All other real
numbers can be represented as integers plus one of the above real numbers.

This example is an instance of Cantor's diagonal argument, which should be
known by all computer scientists.

peter

PS:  The fractional parts of ALL real numbers are infinite.  Some
fractional parts are really boring, ending with an infinite sequence of
0's, and thus can be ignored.  Some fractional parts are moderately boring,
ending with a repeating finite sequence, and thus can be *easily* finitely
represented.
Received on Friday, 4 January 2002 11:51:01 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Monday, 7 December 2009 10:51:52 GMT