Mon, 16 May 2016

15:45 - 16:45
L6

Volumes of minimal hypersurfaces and stationary geodesic nets

Yevgeni Liokumovich
(Imperial College)
Abstract

We will prove an upper bound for the volume of a minimal
hypersurface in a closed Riemannian manifold conformally equivalent to
a manifold with $Ric > -(n-1)$.  In the second part of the talk we will
construct a sweepout of a closed 3-manifold with positive Ricci
curvature by 1-cycles of controlled length and prove an upper bound
for the length of a stationary geodesic net. These are joint works
with Parker Glynn-Adey (Toronto) and Xin Zhou (MIT).

Mon, 09 May 2016

15:45 - 16:45
L6

Finding infinity inside Outer space

Karen Vogtmann
(Warwick University)
Abstract

Motivated by work of Borel and Serre on arithmetic groups, Bestvina and Feighn defined a bordification of Outer space; this is an enlargement of Outer space which is highly-connected at infinity and on which the action of $Out(F_n)$ extends, with compact quotient. They conclude that $Out(F_n)$ satisfies a type of duality between homology and cohomology.  We show that Bestvina and Feighn’s  bordification can be realized as a deformation retract of Outer space instead of an extension, answering some questions left open by Bestvina and Feighn and considerably simplifying their proof that the bordification is highly connected at infinity.

Active Policy Learning for Robot Planning and Exploration under Uncertainty
Martinez-Cantin, R de Freitas, N Doucet, A Castellanos, J 321-328 (25 Jan 2008)
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