%0 Journal Article %T Three-Branes and Five-Branes in N=1 Dual String Pairs %A B. Andreas %A G. Curio %J Physics %D 1997 %I arXiv %R 10.1016/S0370-2693(97)01342-7 %X In this note we show that in dual N=1 string vacua provided by the heterotic string on an elliptic Calabi-Yau together with a vector bundle respectively F-theory on Calabi-Yau fourfold the number of heterotic fivebranes necessary for anomaly cancellation matches the number of F-theory threebranes necessary for tadpole cancellation. This extends to the general case the work of Friedman, Morgan and Witten, who treated the case of embedding a heterotic $E_8\times E_8$ bundle, leaving no unbroken gauge group, where one has a smooth Weierstrass model on the F-theory side. %U http://arxiv.org/abs/hep-th/9706093v2