Stringy Instability of Topologically Non-Trivial Ads Black Holes and of desitter S-Brane Spacetimes

摘要: Seiberg and Witten have discussed a specifically "stringy" kind of instability which arises in connection with "large" branes asymptotically AdS spacetimes. It is easy to see that this actually most five-dimensional black hole string spacetimes non-trivial horizon topologies. We point out more serious problem than it may at first seem, for cannot be resolved even by taking into account the effect on geometry spacetime. [It ultimately due {\em topology} spacetime, not its geometry.] Next, assuming validity some dS/CFT correspondence, we argue deSitter versions Hull-Strominger-Gutperle S-brane are also unstable "topological" sense, least case where R-symmetries preserved. conjecture unrestrained creation "late" branes, spacelike analogue large very late cosmological times.