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Small World
Aug 23, 2007 5:04:03 PM Aug 23, 2007 5:04:03 PM urner@alumni.princeton.edu 0 http://mathforum.org/kb/thread.jspa?messageID=5851408&tstart=0#5851408 postulate.

There're also the definitions you might want to play
with.]]> Aug 11, 2007 2:18:39 PM Aug 11, 2007 2:18:39 PM urner@alumni.princeton.edu 1 http://mathforum.org/kb/thread.jspa?messageID=5850426&tstart=0#5850426
themathpage.com
]]> Aug 10, 2007 5:10:19 PM Aug 10, 2007 5:10:19 PM nycfunction 0 http://mathforum.org/kb/thread.jspa?messageID=5788019&tstart=0#5788019 > 2. If I assume that a Euclidean geometry refers to an
> infinite plane
> surface which]]> Jun 25, 2007 7:23:34 AM Jun 25, 2007 7:23:34 AM george.ivey@gallaudet.edu 0 http://mathforum.org/kb/thread.jspa?messageID=5737784&tstart=0#5737784 May 21, 2007 7:29:07 PM May 21, 2007 7:29:07 PM mathwonk 0 http://mathforum.org/kb/thread.jspa?messageID=4518518&tstart=0#4518518 I think the other reason to focus on negations of the fifth postulate,
instead of the first, is that without the first postulate we]]> Mar 8, 2006 3:07:50 PM Mar 8, 2006 3:07:50 PM joshua.zucker@gmail.com 1 http://mathforum.org/kb/thread.jspa?messageID=4515066&tstart=0#4515066
Let me try to answer some of your not-unreasonable questions. This might
be of some general interest.

1. The importance of]]> Mar 8, 2006 1:15:48 AM Mar 8, 2006 1:15:48 AM wildberger@pacific.net.au 0 http://mathforum.org/kb/thread.jspa?messageID=4514119&tstart=0#4514119
I am trying to understand the motivation behind non-Euclidean geometry.


1. I do not understand why Euclid's fifth postulate is]]> Mar 7, 2006 5:42:26 PM Mar 7, 2006 5:42:26 PM rcanand@gmail.com 7