FOM: sharp boundaries/tameness
kanovei at wmwap1.math.uni-wuppertal.de
Wed Feb 13 12:17:36 EST 2002
>Date: Wed, 13 Feb 2002 10:26:35 -0500
>From: Harvey Friedman <friedman at math.ohio-state.edu>
there is no formula of set theory, phi(x), such that ZFC proves
i) there exists a unique x such that phi(x);
ii) x is such a proper elementary extension.
To this statement, can a reference be given?
A standard Luxemburg construction of a nonmeasurable
set does not really work in the Solovay model because
elements of a definable "nonstandard universe" are not
necessarily themselves definable.
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