From: Tom Goodwillie <tomg@math.brown.edu>
Subject: Re: embedding question
Date: Sat, 3 Feb 2001 03:30:10 +0000


>Which exotic 7-spheres can embed in R^8?

Only the standard 7-sphere embeds in R^8, and there's nothing special about
7. In fact, a Mayer-Vietoris and van Kampen argument shows that the bounded
region in R^8 bounded by a homotopy sphere must be contractible. So by the
h-cobordism theorem it must be a standard sphere (bounding a standard disk).

Tom Goodwillie

Tom Goodwillie