Network analysis of named entity interactions in written texts
Table 1: Statistical properties of NE networks. In most of the networks, the clustering coefficient is higher than the same quantity observed in equivalent random networks. With regard to the average shortest path lengths, the values observed in real and equivalent random networks are similar. Concerning the differences across books, we have identified that most fluctuations arise from the difference in network size (result not shown). However, in specific cases (such as the value of ⟨k⟩ in MAN and PER), the statistical differences are significative, as a consequence of distinct authors’ styles. Such differences could be explored in further studies aiming at identifying authorship in texts.
['[BOLD] Book', '[ITALIC] N', '⟨ [ITALIC] k⟩', '⟨ [ITALIC] C⟩', '⟨ [ITALIC] C⟩r', '⟨ [ITALIC] l⟩', '⟨ [ITALIC] l⟩r']
To probe the topological properties of NE networks, the following quantities were computed: the number of nodes (N), the average degree (⟨k⟩), the clustering coefficient (⟨C⟩) and the average shortest path length (⟨l⟩). In order to compare the properties of NE and random networks, the values of clustering coefficient and average shortest path length in equivalent random networks were also computed as: ⟨C⟩r=⟨k⟩/N, (6) ⟨l⟩r= logN. (7) The results for the full dataset are shown in Table S3 of the SI. From a qualitative point of view, NE and small-world networks share similar topological properties, because in most cases ⟨C⟩≫⟨C⟩r and ⟨l⟩≃⟨l⟩r. Even though the Zipf’s law may play a role in the observed small-world effect, the equivalence between these two effects is not straightforward because, in the proposed model, we consider segments of texts, where a quantity of K entity occurrences does not imply the formation of K edges. An example of NE network is shown in Fig. S5 of the SI. As expected, central characters play a prominent role on the networked model. Another important feature of NE networks is their modular structure. In Fig. S4 of the SI). This modular structure has been noted in most of the studied networks.