Mathematical logic seminar - Feb 11 2020

Time: 3:30pm - 4:30 pm

Room: Wean Hall 8220

Speaker:     Garrett Ervin    
CMU

Title: Distinct orders that divide one another on both sides

Abstract:

We construct two linear orders X and Y that are both left and right factors of one another, but are not isomorphic. The construction of X and Y uses a general theorem characterizing orders whose isomorphism type is invariant when multiplied on the left or right by a given order. Establishing their non-isomorphism relies on a fixed point theorem for the order (ω1* + ω1)ω.