Department of Computer Science | Institute of Theoretical Computer Science | CADMO

Theory of Combinatorial Algorithms

Prof. Emo Welzl and Prof. Bernd Gärtner

Mittagsseminar (in cooperation with A. Steger, D. Steurer and B. Sudakov)

Mittagsseminar Talk Information

Date and Time: Thursday, November 07, 2019, 12:15 pm

Duration: 30 minutes

Location: OAT S15/S16/S17

Speaker: Hung Hoang

Lattice Quotients of the Weak Order

It is well known that the set of all permutations can be given a structure of a partial order, commonly known as the weak order of permutations, which forms a lattice. We consider all the equivalence relations that respect the join and meet operations on this lattice. Every such equivalence relation defines another lattice, called a lattice quotient. The lattice quotients of the weak order generalise many known lattices, such as the Tamari lattice, the (type A) Cambrian lattices, the boolean lattice, the permutree lattices, etc. Recently, Pilaud and Santos realised all those lattice quotients as polytopes, called quotientopes, which generalise hypercubes, associahedra, permutahedra, etc.

In this talk, I will present the properties of the cover graphs of all the lattice quotients. In particular, I will discuss the minimum/maximum degrees and the characterisations and counts of such graphs that are regular and vertex-transitive.

Joint work with Torsten Mütze.

Upcoming talks     |     All previous talks     |     Talks by speaker     |     Upcoming talks in iCal format (beta version!)

Previous talks by year:   2024  2023  2022  2021  2020  2019  2018  2017  2016  2015  2014  2013  2012  2011  2010  2009  2008  2007  2006  2005  2004  2003  2002  2001  2000  1999  1998  1997  1996  

Information for students and suggested topics for student talks

Automatic MiSe System Software Version 1.4803M   |   admin login