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Mathematics Colloquium

Tuesday, January 9, 2018
4:00pm to 5:00pm
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East Bridge 201 (Richard P. Feynman Lecture Hall)
Subgroup non-separability that arises from hyperbolic 3-manifold groups
Hongbin Sun, Department of Mathematics, Rutgers University,
Subgroup separability is a purely group theoretical property that topologists are interested in. It is related with lifting a \pi_1-injective immersed object to be embedded in some finite cover, and in particular the virtual Haken conjecture. In this talk, I will give many new examples of subgroup non-separable groups that come from topology. These groups include: groups of mixed 3-manifolds, amalgamation of finite volume hyperbolic 3-manifold groups along geometrically finite subgroups, and most arithmetic hyperbolic manifold groups with dimension at least 4. The proof of subgroup non-separability heavily uses consequences and tools of Agol's works on subgroup separability of hyperbolic 3-manifold groups.
For more information, please contact Mathematics Department by phone at 626-395-4335 or by email at [email protected].