Indexed on: 04 Apr '17Published on: 04 Apr '17Published in: arXiv - High Energy Physics - Theory
In the previous paper , we showed how to introduce vector gauge fields $A^N_a$ and $A^D_i$ at the end-points of open string in order to enable open string invariance under local gauge transformations of the Kalb-Ramond field and its T-dual "restricted general coordinate transformations". We demonstrated that gauge fields $A^N_a$ and $A^D_i$ are T-dual to each other and that they complete one $D$ dimensional vector. In the present article we prove that all above results can be interpreted as coordinate permutations in double space. So, in the open string case complete set of T-duality transformations form the same subgroup of the $2D$ permutation group as in the closed string case.