Actually no. The equivalence of FTL travel to time travel is established by Special Relativity, which deals with Euclidean universes. It depends on simultaneity not being invariant. You don't need General Relativity (which deals with non-Euclidean universes) to demonstrate that FTL travel is time travel.
Mmm. Thank you. I'd forgotten about that when my brain as-ploded when I started in on tensor calculus. I will cheerfully admit I don't quite understand it, even though I can grasp time dilation, and the explanations of time travel always seem to lose me.
--Devin