The great-grandparent comment was talking about an "information density limit" and black holes in our universe, so I assumed the referenced sci-fi collection had something to do with holography. I don't know of any particular emphasis on AdS in that context before 1997. Elaborate?
Obviously you can stick GR in AdS, but AFAIK nothing about that would've seemed interesting with regards to holography before Maldacena, let alone plausibly providing inspiration to a fiction author.
To be less roundabout than my previous comment: I think Baxter may have been inspired by the holographic principle in general, but I doubt AdS crossed his mind at all when he was writing these stories in the 80s and early 90s.
(EDIT: or maybe Baxter was thinking about AdS but not about holography. I haven't read his work.)
Vacuum Diagrams is a collection of short stories Stephen Baxter has written well before 1997, but the published collection in 1997 included new intertwining narrative stories about an AI named EVE to bind them together. EVE is an AI in a black hole? On the edge of one?
Stephen Baxter is known for sch-fi so hard it'll cut you. He may have just accidentally come up with similar concepts during the same year.
