Rhetorical Structure Theory: Analysis of Aesthetics and Complexity of Song Poetry

The rhetorical structure theory is an instrument for text analysis. The idea of this theory is to consider the text as a system of its relational propositions which are the rhetorical relations between the actual propositions. The rhetorical structure of the text reflects its cognitive and semantic aspects. The assumption being tested in this research is that one can use this theory for analyzing aesthetics and complexity of the literary text. Song poetry became the object of this research because it is the most accessible and popular form of literature nowadays. In the course of the research, structural and lexical criteria for identifying the rhetorical relations for the Russian language were formulated. The main result of this research were the metrics of rhetorical complexity and informational aesthetics. The rhetorical complexity is based on the numerical characteristics of the rhetorical trees such as their height and the number of elements in them. The informational aesthetics is initially the value which depends on the entropy of the sign system, and there are different ways to calculate entropy of the rhetorical structure. All the proposed metrics were checked by a survey, and some of them are significantly more accurate than others. The corpus for this research contains 40 texts and 1228 identified relations. The number of different rhetorical relations for this work is 34. The future expansion of this corpus will provide an opportunity for a more accurate assessment of the metrics.