Self-joinings are like convex cocompact groups with “small” critical exponents

Mon Sep 19, 2022 4:00 p.m.—5:00 p.m.
Exterior of Sheffield-Sterling-Strathcona Hall featuring a stone carving of Yale's coat of arms and motto

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Seminar: 
Group Actions, Geometry and Dynamics

Event time: 
Monday, September 19, 2022 - 4:00pm

Location: 
LOM 206

Speaker: 
Hee Oh

Speaker affiliation: 
Yale

Event description: 
For a convex cocompact  Kleinian group Γ<SO(n,1),  Sullivan (around 1985) established a fundamental relation among the critical exponent, the bottom of the L^2-spectrum of  the hyperbolic manifold Γ∖Hn,  the quasi-regular representation L2(Γ∖G) and the Hausdorff dimension of the limit set.  We consider a higher rank analogue of this relation. For self-joinings of convex cocompact Kleinian groups (or more generally for any Anosov subgroup of a product of rank one simple algebraic groups), we discover a surprising fact that they satisfy  a similar relation as convex cocompact groups with “small” critical exponents.

This talk is based on joint works with Dongryul Kim and Yair Minsky, and with Sam Edwards in different parts.