Published online by Cambridge University Press: 12 March 2014
Our results concern the existence of a countable extension of the countable atomless Boolean algebra
such that
is a “nonconstructive” extension of
. It is known that for any fixed admissible indexing φ of
there is a countable nonconstructive extension
of
(relative to φ). The main theorem here shows that there exists an extension
of
such that for any admissible indexing φ of
,
is nonconstructive (relative to φ).Thus, in this sense
a countable totally nonconstructive extension of
.