BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Discrete Mathematics Group - ECPv6.15.20//NONSGML v1.0//EN
CALSCALE:GREGORIAN
METHOD:PUBLISH
X-ORIGINAL-URL:https://dimag.ibs.re.kr
X-WR-CALDESC:Events for Discrete Mathematics Group
REFRESH-INTERVAL;VALUE=DURATION:PT1H
X-Robots-Tag:noindex
X-PUBLISHED-TTL:PT1H
BEGIN:VTIMEZONE
TZID:Asia/Seoul
BEGIN:STANDARD
TZOFFSETFROM:+0900
TZOFFSETTO:+0900
TZNAME:KST
DTSTART:20210101T000000
END:STANDARD
END:VTIMEZONE
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20220525T163000
DTEND;TZID=Asia/Seoul:20220525T173000
DTSTAMP:20260419T113922
CREATED:20220525T073000Z
LAST-MODIFIED:20240705T172235Z
UID:5509-1653496200-1653499800@dimag.ibs.re.kr
SUMMARY:Sebastian Siebertz\, Transducing paths in graph classes with unbounded shrubdepth
DESCRIPTION:Transductions are a general formalism for expressing transformations of graphs (and more generally\, of relational structures) in logic. We prove that a graph class C can be FO-transduced from a class of bounded-height trees (that is\, has bounded shrubdepth) if\, and only if\, from C one cannot FO-transduce the class of all paths. This establishes one of the three remaining open questions posed by Blumensath and Courcelle about the MSO-transduction quasi-order\, even in the stronger form that concerns FO-transductions instead of MSO-transductions. \nThe backbone of our proof is a graph-theoretic statement that says the following: If a graph G excludes a path\, the bipartite complement of a path\, and a half-graph as semi-induced subgraphs\, then the vertex set of G can be partitioned into a bounded number of parts so that every part induces a cograph of bounded height\, and every pair of parts semi-induce a bi-cograph of bounded height. This statement may be of independent interest; for instance\, it implies that the graphs in question form a class that is linearly chi-bounded. \nThis is joint work with Patrice Ossona de Mendez and Michał Pilipczuk.
URL:https://dimag.ibs.re.kr/event/2022-05-25/
LOCATION:Zoom ID: 869 4632 6610 (ibsdimag)
CATEGORIES:Virtual Discrete Math Colloquium
END:VEVENT
END:VCALENDAR