  Despite its importance, the task of summarizing evolving events has received
small attention by researchers in the field of multi-document summariztion. In
a previous paper (Afantenos et al. 2007) we have presented a methodology for
the automatic summarization of documents, emitted by multiple sources, which
describe the evolution of an event. At the heart of this methodology lies the
identification of similarities and differences between the various documents,
in two axes: the synchronic and the diachronic. This is achieved by the
introduction of the notion of Synchronic and Diachronic Relations. Those
relations connect the messages that are found in the documents, resulting thus
in a graph which we call grid. Although the creation of the grid completes the
Document Planning phase of a typical NLG architecture, it can be the case that
the number of messages contained in a grid is very large, exceeding thus the
required compression rate. In this paper we provide some initial thoughts on a
probabilistic model which can be applied at the Content Determination stage,
and which tries to alleviate this problem.
