BIU Infinite Combinatorics Seminar
Date : 31/12/2018 – 13:00 – 15:00
Speaker: Miguel Moreno (BIU)
Title : An introduction to generalized descriptive set theory, part 2
Abstract. After introducing the notions of $\kappa$-Borel class, $\kappa$-$\Delta_1^1$ class, $\kappa$-Borel^* class in the previous talk, in this talk, we will show the relation between this classes.
In descriptive set theory the Borel class, the $\Delta_1^1$ class, the Borel* class are the same class, this doesn’t hold in the generalized descriptive set theory, in particular under the assumption V=L the Borel* class is equal to the $\Sigma1^ 1$ class.