April 2018
Marek Bienias: About universal structures and Fraisse theorem
22/04/18 07:56
Tuesday, April 24, 2018 17:15
Room: D1-215
Speaker: Marek Bienias
Title: About universal structures and Fraisse theorem
Abstract. For a given structure D of language L we can consider age of D, i.e. the family of all finitely generated L-substructures od D. It turns out that age has property (HP) and (JEP). Fraisse theorem let us revers the procedure: if K is nonempty countable family of finitely generated L-structures having properties (HP), (JEP) and (AP), then there exists exactly one (up to isomorphism) L-structure D (so called Fraisse limit) which is countable ultrahomogenous and has age K.
The aim of the talk is to define basic notions from Fraisse theory, proof the main theorem and show some alternative way of looking at the construction of Fraisse limit.
Room: D1-215
Speaker: Marek Bienias
Title: About universal structures and Fraisse theorem
Abstract. For a given structure D of language L we can consider age of D, i.e. the family of all finitely generated L-substructures od D. It turns out that age has property (HP) and (JEP). Fraisse theorem let us revers the procedure: if K is nonempty countable family of finitely generated L-structures having properties (HP), (JEP) and (AP), then there exists exactly one (up to isomorphism) L-structure D (so called Fraisse limit) which is countable ultrahomogenous and has age K.
The aim of the talk is to define basic notions from Fraisse theory, proof the main theorem and show some alternative way of looking at the construction of Fraisse limit.
Piotr Borodulin-Nadzieja: Tunnels through topological spaces
13/04/18 14:36
Tuesday, April 17, 2018 17:15
Room: D1-215
Speaker: Piotr Borodulin-Nadzieja
Title: Tunnels through topological spaces
Abstract. I will show a ZFC example of a compact space (without isolated points) through which one cannot drill a tunnel. I will discuss when and when not \(\omega^*\) has a tunnel.
Room: D1-215
Speaker: Piotr Borodulin-Nadzieja
Title: Tunnels through topological spaces
Abstract. I will show a ZFC example of a compact space (without isolated points) through which one cannot drill a tunnel. I will discuss when and when not \(\omega^*\) has a tunnel.