Set Theory and Topology seminar (BGU)
Time: Tuesday, May 26, 12:15–13:40.
Place: Seminar room -101, Math building 58.
Speaker: Grigory Mashevitsky (BGU).
Title: Identical inclusions of semilattices.
The class of identical inclusions was defined by E. S. Lyapin. I’ll briefly explain this concept its connections and possible applications. An identical inclusion is a non elementary formula in general. I’ll illustrate this concept describing the infinite lattice of classes of semilattices which can be defined by systems of identical inclusions. It is interesting and even surprising that any system of identical inclusions in the class of semilattices is equivalent to an elementary (the first order) formula.
If time permits I’ll explain how algorithms which solves the main problems concerning identical inclusions of semilattices can be constructed.