Aspects of two-dimensional dilaton gravity, dimensional reduction, and holography

We discuss aspects of generic two-dimensional dilaton gravity theories. The geometry is in general conformal to the anti--de Sitter space (${\mathrm{AdS}}_{2}$) and has IR curvature singularities at zero temperature; this can be regulated by a black hole. on-shell action divergent; we holographic energy-momentum tensor adding appropriate counterterms. For theories obtained dimensional reduction gravitational sector higher theories, for instance AdS as concrete example, description dovetails with one. also more containing an extra scalar field which now drives nontrivial dynamics. Finally cosmological discussed earlier work. These studies suggest that are somewhat distinct from Jackiw-Teitelboim (JT) ``near JT''.