Description of intersecting branes via tachyon condensation

We construct a model describing BPS brane-systems using low energy effectiv e theory of brane-antibrane system. Both parallel branes and intersecting b ranes can be treated by this model. After tachyon condensation, the dynamic s of fluctuations around such brane-systems is supersymmetric if the degree s of freedom are restricted on the branes. The form of the tachyon potentia l and the application of this model to the black hole physics are discussed . (C) 2000 Elsevier Science B.V, All rights reserved.