Dependence balance bounds for single-output two-way channels

If in a transmission the inputs of a single-output two-way channel exhibit some interdependence, this dependence must have been created during earlier transmissions. The idea that no more dependence can be consumed than produced is used to obtain new upper bounds to the capacity region of the discrete memoryless single-output two-way channel. With these upper bounds we can show that Shannon's inner bound region is the capacity region for channels in a certain class and improve upon the Zhang-Berger-Schalkwijk upper bound for Blackwell's multiplying channel.