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Durham University

Research & business

Research lectures, seminars and events

The events listed in this area are research seminars, workshops and lectures hosted by Durham University departments and research institutes. If you are not a member of the University, but  wish to enquire about attending one of the events please contact the organiser or host department.


Pure Maths Colloquium: Surface subgroups of graphs of free groups

Presented by Henry Wilton, University of Cambridge
27 January 2020 13:00 in CM101

Hyperbolic groups, introduced by Gromov and others in the 1980s, are discrete groups that satisfy a coarse negative curvature condition. The simplest examples are free groups and surface groups (i.e. the fundamental groups of negatively curved surfaces). Around the time of their introduction, Gromov famously asked a natural question: must a hyperbolic group G contain a surface subgroup, unless it has a free subgroup of finite index? I will describe recent progress in the case when G is the fundamental group of a graph of free groups (for instance, an amalgamated product F_1 *_H F_2).

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