2005 seminar talk: Methods for solving universality problems
Talk held by Katie Thompson (KGRC) at the KGRC seminar on 2005-10-06.
We will discuss a number of ways of showing that universal models do or do not exist. The methods stem from model theory, set theory and category theory. We will see examples of these methods mostly using relational structures, but they can be applied to algebraic and topological structures as well. By comparing which methods work for different structures, one can find patterns in the behaviour of these structures with regard to universality.