Recently the number of applications in the Internet which use data broad­casts, such as pay-per-view services, has increased greatly. In broadcast scheduling one is interested in answering user requests in such services with as little bandwidth as possible by bundling the answers appropriately. Flows over time are an important notion arising in connection with various appli­cations in communication and transportation networks. One of the basic question here is how can demands in a given network be routed to their destinations as quickly as possible? Economic relationships in the Internet...