Summarizing Reports on Evolving Events - Part II: Non-Linear Evolution

News sources, when covering an event, are emitting various reports during the course of the event’s evolution. This paper focuses on the task of summarizing such reports. After discussing the nature of evolving events (dividing them into linearly and non-linearly evolving events), we present a methodology for the creation of summaries of evolving events as they are being described by multiple sources. At the core of this methodology lies the notion of Synchronic and Diachronic Relations (SDRs) whose aim is the identification of similarities and differences across documents. SDRs do not connect textual elements inside the text but some structures which we call messages. We present the application of our methodology via a case study.