**Three-dimensional gravity: a superb theoretical laboratory**

Abstract:

Three-dimensional Einstein gravity has no local dynamical degree of freedom. Yet, it is far from being trivial when the cosmological constant
is negative. (i) It admits black hole solutions. (ii) It possesses remarkable asymptotic properties at infinity where an infinite-dimensional symmetry
algebra emerges. These unique features make three-dimensional gravity a perfect "theoretical laboratory" in which to explore the conceptual issues
related to (i) and (ii) in a simpler context. The talk will not only discuss three-dimensional gravity assuming no previous knowledge on the subject,
but will also provide background information on why (i) and (ii) are connected with some of the deepest current challenges in physics.

Note that the colloquium will take place at the Vienna University of Technology, Wiedner Hauptstrasse 8-10, FH HS 5 (2nd floor, green tower)