Abstract. In this paper, motivated by applications of ordinary (distance) spanners in communication networks and to address such issues as bandwidth constraints on network links, link failures, network survivability, etc., we introduce a new notion of flow spanner, where one seeks a spanning subgraph H = (V, E ) of a graph G = (V, E) which provides a “good” approximation of the source-sink flows in G. We formulate few variants of this problem and investigate their complexities. A special attention is given to the version where H is required to be a tree.
Feodor F. Dragan, Chenyu Yan