BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Jakub Byszewski (Jagellonian University) DTSTART:20201019T111500Z DTEND:20201019T121500Z DTSTAMP:20260423T022917Z UID:WarsawNT/8 DESCRIPTION:Title: Finite order automorphisms of the ring of power series over a finite fiel d\nby Jakub Byszewski (Jagellonian University) as part of Warsaw Numbe r Theory Seminar\n\nLecture held in room 403 at IMPAN.\n\nAbstract\nThe No ttingham group at a prime $p$ is the group of (formal) power series $t+a_2 t^2+ a_3 t^3+ \\cdots$ in the variable $t$ with coefficients $a_i$ from t he field with $p$ elements with the group operation given by composition o f power series. This group is known to contain elements of order being an arbitrary power of $p$. Elements of order $p$ have been classified by Klop sch and have a nice description. For higher orders\, however\, only a hand ful of examples have been known explicitly.\n\nIn the talk we will show ho w to describe such series in closed computational form through finite auto mata. This allows us to construct many explicit examples and formulate a n umber of questions. The talk is based on joint work with Gunther Corneliss en and Djurre Tijsma.\n LOCATION:https://researchseminars.org/talk/WarsawNT/8/ END:VEVENT END:VCALENDAR