Complex structures, T-duality and worldsheet instantons in Born sigma models

We investigate doubled (generalized) complex structures in $2D$-dimensional Born geometries where T-duality symmetry is manifestly realized. show that K\"{a}hler, hyperk\"{a}hler, bi-hermitian and bi-hypercomplex of spacetime are implemented as structures. find the generalized K\"{a}hler (hyperk\"{a}hler) appear subalgebras bi-quaternions split-tetra-quaternions. parts these classified by Clifford algebras. then study nature worldsheet instantons sigma models. related to those a non-trivial way.