Capacity of sum-networks for different message alphabets
Is Version Of
A sum-network is a directed acyclic network in which all terminal nodes demand the `sum' of the independent information observed at the source nodes. Many characteristics of the well-studied multiple-unicast network communication problem also hold for sum-networks due to a known reduction between instances of these two problems. Our main result is that unlike a multiple unicast network, the coding capacity of a sum-network is dependent on the message alphabet. We demonstrate this using a construction procedure and show that the choice of a message alphabet can reduce the coding capacity of a sum-network from 1 to close to 0.
This is a manuscript of a proceeding from the IEEE International Symposium on Information Theory (2015): 606, doi:10.1109/ISIT.2015.7282526. Posted with permission.