# Gravity in a box Asymptotically anti-de Sitter space is usually said to behave like a box. But that is not quite literally true: gravity in a box, i.e., gravity in a finite region of space, shares features with AdS space but is less well-behaved. There are questions about the variational principle, well-posedness of the initial-boundary value problem, etc. ## Refs - [[2024#Liu, Santos, Wiseman]]: a one-parameter family of boundary conditions generalising Dirichlet and Anderson - [[2024#Miyashita]]: Einstein-Maxwell system in a box; no [[0012 Hawking-Page transition|HP transition]] unless [[0281 Bag-of-gold spacetime|bag-of-gold]] spacetimes are considered