  Transport through two one-dimensional interacting metals (Luttinger liquids)
coupled together at a single point is analyzed. The dominant coupling mechanism
is shown to be of electrostatic nature. Describing the voltage sources by
boundary conditions then allows for the full solution of the transport problem.
For weak Coulomb interactions, transport is unperturbed by the coupling. In
contrast, for strong interactions, unusual nonlinear conductance laws
characteristic for the correlated system can be observed.
