### Borel sets without perfectly many overlapping translations

by Roslanowski and Shelah. [RoSh:1138]

For a cardinal lambda < lambda_{omega_1} we give a ccc
forcing notion P such that in V^P there is a Sigma^0_2 set
B subseteq {}^omega 2 with a sequence < eta_alpha :
alpha < lambda > of distinct elements of {}^omega 2 such that
|(eta_alpha +B) cap (eta_beta +B) | >= 6 for all
alpha, beta < lambda but does not have a perfect set of such
eta 's. The construction closely follows the one from
[Sh:522, Section 1].

Back to the list of publications