RE: virus: Re: alternative model
Schneider John (JSCHNEID@hanoverdirect.com)
Thu, 12 Dec 1996 02:26:11 -0500
Kenneth Boyd wrote:
[clip]
> For instance, less than 5 years ago, it was shown that R^4 
> [4-D space] has as many distinct "differential structures" as 
> the real numbers.  In other words, a sufficiently bad choice of 
> "differential structure" will make functions you expect to have 
> reasonable tangent lines, *fail* to have tangent lines.  This is 
> unique to 4-D space; for any other [finite-dimensional] space, 
> the functions you expect to have tangent lines always do [there 
> is effectively only one "differential structure", in terms of 
> the functions that have tangent lines.]
>
> Unfortunately, the proof was nonconstructive: it doesn't tell 
> how to construct any of these "weird" spaces.
I assume it's well over my head, but could you give a reference 
to the paper which outlined the proof?  (I assume that paper will 
contain all the other relevant references).  I'm interested in 
theorems which distinguish between spaces like that.  Thanks.
- JPSchneider
- jschneid@hanoverdirect.com