Formalizing a model to represent and visualize concept spaces in e-learning environments

Zz-structures offer graph-centric views capable of representing contextual interconnections among different information. In this paper we use them to represent and visualize concept space in e-learning environments and we present their formal analytic description in terms of graph theory. In particular, we focus our attention on the formal description of two views (H and I views), and we extend these notions to a number n > 2 of dimensions. We also apply both formal description, together with the particular properties of zz-structures, to an example in the Web-based education field.