37th International Symposium on Theoretical Aspects of Computer Science, STACS 2020, March 10-13, 2020, Montpellier, France (Christophe Paul and Markus Bläser), volume 154 of LIPIcs, pages 13:1-13:17, 2020, Schloss Dagstuhl - Leibniz-Zentrum für Informatik.