# Seminario - Ladder systems on omega_1 and some topological examples.

Martedi’ 16 Ottobre, alle ore 10:00, in aula seminari, il professor Paul Szeptycki della York University di Toronto, Canada, terra’ un seminario dal titolo: “Ladder systems on $\omega_1$ and some topological examples”.

Title: Ladder systems on $\omega_1$ and some topological examples.
Abstract: Ladder systems on the first uncountable ordinal can be used to construct interesting counterexamples in the theory of covering and separation axioms in topological spaces. We consider the open question whether there is a ladder system with a weak uniformization property and a strong anti-uniformization property -- such a ladder system would answer two open questions from topology. Some recent results will be discussed.