[Settfa] Seminar 12 September 2023

[Wieslaw Kubis]

Wiesław Kubiś

IM CAS

An ordinal rank measuring universality

<https://www.math.cas.cz/index.php/events/event/3610>

IM CAS, Konirna

We shall discuss a natural ordinal rank on countable structures that 
measures how complicated the structure is. It is in the spirit of the 
Cantor-Bendixson rank for scattered topological spaces, although the 
formal definition is different. Under some natural assumptions, a 
structure has infinite rank if and only if it is universal. We shall 
discuss some illustrative examples.