diff --git a/seminar.md b/seminar.md index a0871d51bc12d724cc26dbbfe678dcedd34a3b2a..3a9116fa8ef0b609f8d55481e949a24627bd88bb 100644 --- a/seminar.md +++ b/seminar.md @@ -2,6 +2,44 @@ Pour tout renseignement ou proposition de séminaire, merci de contacter [Cyril Pain-Barre](mailto:cyril.pain-barre@lis-lab.fr). +### Mercredi 19 juin 2024 à 15h + ++ Date & Heure : Mercredi 19 juin 2024 à 15h + ++ Lieu : Salle de réunion COALA, dans les locaux de l'équipe. + ++ Orateur : Benjamin BERGOUGNOUX, Postdoc à l'université de Varsovie, Pologne + ++ Information(s) diverse(s) : exposé en anglais + ++ Titre : Neighborhood operator logics: efficient model checking in terms of width parameters + ++ Résumé : In this talk, I will introduce the family of neighborhood operator (NEO) logics which are extensions of existential MSO with predicates + for querying neighborhoods of vertex sets. + NEO logics have interesting modeling powers and nice algorithmic applications for several width parameters such as tree-width. + NEO logics capture many important graphs problems such as Independent Set, Dominating Set and many of their variants. + Moreover, some NEO logics capture CNF-SAT via the signed incidence graphs! + We can capture more problems by considering various extensions of NEO logics. + For example, we can capture problems with global constraints such as Hamiltonian Cycle via the extension of NEO logics + with predicates for checking the connectivity/acyclicity of vertex sets. + + In terms of algorithmic applications, NEO logics seem to be the perfect candidates for capturing many problems + that can be solved efficiently in terms of width parameters. + + This is suggested by the following three results: + + - For tree-width, the most powerful NEO logics can be model checked in single exponential time in terms of tree-width + as implied by a result of Michal Pilipczuk [MFCS 2011]. + + - Jan Dreier, Lars Jaffke and I proved that, for an extension of one NEO logic, we can obtain an efficient model-checking algorithm + in terms of several width parameters more general than tree-width such as clique-width, rank-width and mim-width [SODA 2023]. + + - Vera Checkan, Giannos Stamoulis and I are currently proving that some NEO logic can be solved in single exponential time and + polynomial space for tree-depth: the shallow restriction of tree-width. + This last result could be interesting in practice where space usage is crucial. + I will present these three results after a friendly introduction on width parameters. + + ### Mercredi 12 juin 2024 à 14h + Lieu : Salle de réunion COALA, dans les locaux de l'équipe.