Comments on D-brane and SO(2n) enhanced symmetry in type II string

Abstract

We propose a configuration of D-branes welded by analogous orbifold operation to be responsible for the enhancement of SO(2N) gauge symmetry in type II string compactified on the D n -type singular limit of K3. Evidences are discussed from the D n -type ALE and D-manifold point of view. A subtlety regarding the ability of seeing the enhanced SO(2N) gauge symmetry perturbatively is briefly addressed.⋆ On leave from Zhejiang University, China