University Seminar: Logic Across Disciplines-Title: Cohesive Powers, Definability, and Automorphisms

Title:   Title: Cohesive Powers, Definability, and Automorphisms

Speaker:    Rumen Dimitrov, Western Illinois University

Date and Time: Friday, December 8  2017, 11:00am-12:00pm

Place: Rome Hall (801 22nd Street), Room 351

Abstract:  In 1959, Feferman, Scott, and Tennenbaum showed that the recursive functions modulo r-cohesive sets are models of only fragments of arithmetic. In 1970, Lerman characterized the isomorphism types of a class of such structures. In 2014, Dimitrov, Harizanov, Miller, and Mourad proved similar results about cohesive powers of the standard presentation of the field of rational numbers. In this talk we will discuss the connection between definability and isomorphisms of cohesive powers of computable structures.