BEGIN:VCALENDAR VERSION:2.0 PRODID:-//132.216.98.100//NONSGML kigkonsult.se iCalcreator 2.20.4// BEGIN:VEVENT UID:20260603T075544EDT-2771CBNag6@132.216.98.100 DTSTAMP:20260603T115544Z DESCRIPTION:Title: The primitive Eulerian polynomial.\n\nAbstract: We intro duce the Primitive Eulerian polynomial $P_mathcal{A}(z)$ of a central hype rplane Arrangement $mathcal{A}$. It is a reparametrization of the cocharac teristic polynomial of the arrangement. Previous work (2021) implicitly sh owed that this polynomial has nonnegative coefficients in the simplicial c ase. If $mathcal{A}$ is the arrangement corresponding to a Coxeter group $ W$ of type A or B\, then $P_mathcal{A}(z)$ is the generating function for the (flag)excedance statistic on a particular subset of $W$. No interpreta tion was found for reflection arrangements of type D.\n \n We present an alt ernative geometric and combinatorial interpretation for the coefficients o f $P_mathcal{A}(z)$ for all simplicial arrangements $mathcal{A}$. For refl ection arrangements of types A\, B\, and D\, we find recursive formulas th at mirror those for the Eulerian polynomial of the corresponding type. We also present real-rootedness results and conjectures for $P_mathcal{A}(z)$ . This is joint work with Christophe Hohlweg and Franco Saliola.\n\nPK-432 3\, UQAM\, 201\, av du Président-Kennedy\n\nWeb site : https://lacim.uqam. ca/seminaires/\n DTSTART:20221007T150000Z DTEND:20221007T160000Z SUMMARY:Jose Bastidas\, LACIM URL:/mathstat/channels/event/jose-bastidas-lacim-34242 9 END:VEVENT END:VCALENDAR