  The recently established metric reduction in generalized geometry is encoded
in 0-dimensional supersymmetric $\sigma$-models. This is an example of balanced
topological field theories. To find the geometric content of such models, the
reduction of Bismut connections is studies in detail. Generalized
K$\ddot{a}$hler reduction is briefly revisited in this formalism and the
generalized K$\ddot{a}$hler geometry on the moduli space of instantons on a
generalized K$\ddot{a}$hler 4-manifold of even type is thus explained formally
in a topological field theoretic way.
