... only) and documents as units to calculate doc- ument frequency, which resulted in the creation offive frequency tables: (i) Mainichi-Document, (ii)Mainichi-Sentence, (iii) Wikipedia-Document, ... (thenumber of documents where the word is found), (2)relative frequenc y (frequency divided by the maxi-mum number of documents), (3) co-occurrence fre-quency (the number of documents where ... definitions from non-definitions on the basisof features related mainly to linguistic styles.In multi-document summarization, the focus hasbeen mainly on creating cohesive texts. (Lapata,2003) uses...