The dual vector space to a real vector space V is the vector space of linear functions f:V->R, denoted V^*. In the dual of a complex vector space, the linear functions take complex values. In either case, the dual vector space has the same dimension as V. Given a vector basis v_1, ..., v_n for V there exists a dual basis for V^*, written v_1^*, ..., v_n^*, where v_i^*(v_j) = δ_(i j) and δ_(i j) is the Kronecker delta.