Publication details

Twin-Width is Linear in the Poset Width

Investor logo
Authors

BALABÁN Jakub HLINĚNÝ Petr

Year of publication 2021
Type Article in Proceedings
Conference International Symposium on Parameterized and Exact Computation (IPEC)
MU Faculty or unit

Faculty of Informatics

Citation
Web https://arxiv.org/abs/2106.15337
Doi http://dx.doi.org/10.4230/LIPIcs.IPEC.2021.6
Keywords twin-width; digraph; poset; FO model checking; contraction sequence
Description Twin-width is a new parameter informally measuring how diverse are the neighbourhoods of the graph vertices, and it extends also to other binary relational structures, e.g. to digraphs and posets. It was introduced just very recently, in 2020 by Bonnet, Kim, Thomasse and Watrigant. One of the core results of these authors is that FO model checking on graph classes of bounded twin-width is in FPT. With that result, they also claimed that posets of bounded width have bounded twin-width, thus capturing prior result on FO model checking of posets of bounded width in FPT. However, their translation from poset width to twin-width was indirect and giving only a very loose double-exponential bound. We prove that posets of width d have twin-width at most 9d with a direct and elegant argument, and show that this bound is asymptotically tight. Specially, for posets of width 2 we prove that in the worst case their twin-width is also equal 2. These two theoretical results are complemented with straightforward algorithms to construct the respective contraction sequence for a given poset.
Related projects:

You are running an old browser version. We recommend updating your browser to its latest version.

More info