"Naked singularities could exist in a pretend 4-D universe called “anti-de Sitter” (AdS) space whose space-time geometry is shaped like a tin can." Can anyone

"Naked singularities could exist in a pretend 4-D universe called “anti-de Sitter” (AdS) space whose space-time geometry is shaped like a tin can." Can anyone further explain the space-time geometry?