Recorded 17 April 2024. Paul Zinn-Justin of the University of Melbourne presents "The MacNeille completion of the type B Bruhat poset" at IPAM's Integrability and Algebraic Combinatorics Workshop. Abstract: Following Lascoux and Schutzenberger, we'll discuss the MacNeille completion of Weyl groups of classical types endowed with (strong) Bruhat order. We'll discuss the connection with Alternating Sign Matrices and provide a new explicit description of it in type B. Learn more online at: https://www.ipam.ucla.edu/programs/workshops/workshop-ii-integrability-and-algebraic-combinatorics/