... in information retrieval, pages 314-321. ACM. Giambattista Amati, Edgardo Ambrosi, Marco Bianc-hi, Carlo Gaibisso, and Giorgio Gambosi. 2007. FUB, IASI-CNR and University of Tor Vergata at ... represented by a bag-of-word. Among the words, there is a topic term Avatar (t1) occurring twice, i.e. Avatar in A and Avatar in C, and two senti-ment words comfortable (o1) and favorite (o2) ... sen-tence A is a factual statement rather than an opi-nion statement. (a) (b) Figure 2: Two kinds of information representa-tion of opinion retrieval. (t1=‘Avatar’ o1= ‘com-fortable’,...