Visualization Techniques in Non Symmetrical Relationships

Many strategies of Text retrieval are based on Latent Semantic Indexing and its variations, by considering different weighting systems for words and documents, Correspondence Analysis and LSI share the basic algebraic tool, i.e. Singular Value decomposition and its generalisations, related to the use of different way for measuring the importance of each element, both in determining and representing similarities between documents and words. Aim of the paper is to propose a peculiar factorial approach for better visualising the relations between textual data and documents, compared with classical Correspondence Analysis. Here we consider a TF/IDF index scheme, mainly developed for Text Retrieval, in a textual data analysis context.