Introduction to better-quasi-orderings

Logic Seminar

Meeting Details

For more information about this meeting, contact Kristin Berrigan, Jan Reimann, Linda Westrick.

Speaker: Linda Westrick, Penn State University

Abstract: We give an introduction to the theory of better-quasi-orderings (BQOs) as defined by Nash-Williams 1965 paper "On well-quasi-ordering infinite trees". Well-quasi-orderings (WQOs), which are quasi-orderings that have no infinite antichains or strictly descending sequences, have been repeatedly and independently defined; the stronger, stranger, but better-behaved notion of a BQO has made it possible to verify the WQO-ness of certain quasi-orders, via showing that they are actually BQO.


Room Reservation Information

Room Number: 315 McAllister

Date: 10/15/2019

Time: 2:30pm - 4:00pm