"Zones of Thought", Vernor Vinges, 1992
It's a series ("The Blabber", A Fire Upon the Deep, A Deepness in the Sky and the forthcoming The Children of the Sky), where computation is easier in some parts of the galaxy, allowing for things like artificial intelligence and FTL travel.
It has been speculated (but there's no direct evidence in the books) that P=NP in these zones.
