$K$-theoretic matching of brane charges in S- and U-duality
$K$-theoretic matching of brane charges in S- and U-duality
We discuss K-theoretic matching of D-brane charges in the string duality between type I on the 4-torus and type IIA on a K3 surface. This case is more complex than the familiar case of IIA/IIB duality, which is already well understood, but it turns out that replacing K3 by its …