Paleogeographic maps are essential tools for understanding Earth system dynamics. They provide boundary conditions climate and geodynamic modelling, analysing surface processes biotic interactions. However, the temporal spatial distribution of key features such as seaways mountain belts that govern changes interchange differ between various paleogeographies require regular updates with new data...

A Hamiltonian framework for 2+1 dimensional gravity coupled with matter (satisfying positive energy conditions) is considered in the asymptotically at context. It is shown that the total energy of the system is non-negative, vanishing if and only if space-time is (globally) Minkowskian. Furthermore, contrary to one's experience with usual eld theories, the Hamiltonian is bounded from above. Thi...