Computability Seminar MSRI program on DDC-Indestructibility on sets of positive upper density

Organizer: V. Harizanov

For link contact [email protected]

Thursday, October 22, 12:00-1:00 ET on Zoom

Speaker: Rehana Patel, AIMS (Senegal) and MSRI

Title: Indestructibility on sets of positive upper density

Abstract: A structure M is said to be indestructible on a subset of its underlying set if the substructure induced on this subset contains a copy of M.  Recently, W. Brian has shown that almost every Rado graph with underlying set the natural numbers is indestructible on any subset of positive upper density.  In this talk I will consider indestructibility, on all subsets of positive upper density, for arbitrary ultrahomogeneous relational structures on the naturals that are Martin-Löf random for some invariant measure.  This is preliminary work, joint with N. Ackerman and C. Freer.