BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Genevieve Walsh (Tufts University) DTSTART:20200428T150000Z DTEND:20200428T153000Z DTSTAMP:20260423T003300Z UID:GaTO/2 DESCRIPTION:Title: Inc oherence of free-by-free and surface-by-free groups\nby Genevieve Wals h (Tufts University) as part of Geometry and topology online\n\nLecture he ld in N/A.\n\nAbstract\nA group is said to be coherent if every finitely g enerated subgroup is finitely presented. This property is enjoyed by free groups\, and the fundamental groups of surfaces and 3-manifolds. A group that is not coherent is incoherent\; it is very interesting to try and u nderstand which groups have which property. We will discuss some of the g eometric and topological aspects of this question\, particularly quasi-con vexity and algebraic fibres. We show that free-by-free and surface-by-fre e groups are incoherent\, when the rank and genus are at least two.\n\nThi s is joint work with Robert Kropholler and Stefano Vidussi.\n LOCATION:https://researchseminars.org/talk/GaTO/2/ END:VEVENT END:VCALENDAR