Abstract
We answer in the affirmative the following question of Jörg Brendle: If there is a $\Sigma^1_2$ mad family, is there then a $\Pi^1_1$ mad family?
Citation
Asger Törnquist. "$\Sigma^1_2$ and $\Pi^1_1$ mad families." J. Symbolic Logic 78 (4) 1181 - 1182, December 2013. https://doi.org/10.2178/jsl.7804080
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