Penrose Diagram for Anti de Sitter Spacetime - Explained

[latentcorpse]

Consider the penrose diagram for anti de sitter spacetime. It looks like the picture at the bottom of this wikipedia page:
http://en.wikipedia.org/wiki/Anti_de_Sitter_space
but sandwiched down I guess.

Anyway, the bit I've just been reading claims that \mathcal{I} (null and spacelike) infinity would be the vertical line on the right hand side bordering the red and black regions in that diagram.
We know that the red bit is our Einstein static universe and the green bit is the physical AdS spacetime - what I want to know is why \mathcal{I^+}, \mathcal{I^-} aren't the diagonal lines on the boundary between the green and red regions as they usually are for penrose diagrams?

Hopefully my question makes sense - I was struggling to find a Penrose diagram of AdS and this was the best I could do!

 

[member 553083]

The vertical line on the right hand side is not actually \mathcal{I^+}, \mathcal{I^-}. Instead, it is a representation of the conformal boundary of AdS spacetime. In AdS spacetime, \mathcal{I^+} and \mathcal{I^-} are located at infinity, which means that they cannot be plotted on thePenrose diagram. The lines shown in the diagram, which border the red and green regions, are merely a visual representation of the conformal boundary, which is the boundary between the physical AdS spacetime and the Einstein static universe.