48 research outputs found
Definable maximal cofinitary groups of intermediate size
Using almost disjoint coding, we show that for each
consistently ,
where is witnessed by a maximal cofinitary
group.Comment: 22 page
Definability of maximal cofinitary groups
We present a proof of a result, previously announced by the second author,
that there is a closed (even ) set generating an (even
) maximal cofinitary group (short, mcg) which is isomorphic to a
free group. In this isomorphism class, this is the lowest possible definitional
complexity of an mcg.Comment: This work is part of the first authors thesi