Towards the algebraic analysis of hyperlink structures

Structuring media objects such as text, graphics etc. by means of XML is a broadly discussed issue in hypermedia modeling. Thereby, an entire hypermedia document is not only arranged in such a way different developers may interchange data and have easy access to the inner structure of media objects by means of powerful tools available in the XML scene. Moreover, utilizing a given document structure to find new possibilities of linking documents is a major concern. Formal approaches, however, rarely appear in this context. In this paper, we contribute to formally structuring media objects and their linkage, thereby aiming at analyzing hyperlink structures. That is, properties of hyperlinks between media objects underlie a mathematical verification in advance of encoding the concrete hyperdocument. Algebraic specifications serve as a formal model allowing to obtain algebras reflecting hyperlink structures open to analysis

Modeling Sequences within the RelView System

We use a relational characterization of binary direct sums to model sequences within the relation-algebraic manipulation and prototyping system RelView in a simple way. As an application we formally derive a RelView program for computing equivalence classes of an equivalence relation, where we combine relation-algebraic calculations with the so-called Dijkstra-Gries program development method. Also a refinement of the simple modeling is presented, which leads to the classical datatype of stacks, and a further application is sketched

Modeling Sequences within the RelView System

We use a relational characterization of binary direct sums to model sequences within the relation-algebraic manipulation and prototyping system RelView in a simple way. As an application we formally derive a RelView program for computing equivalence classes of an equivalence relation, where we combine relation-algebraic calculations with the so-called Dijkstra-Gries program development method. Also a refinement of the simple modeling is presented, which leads to the classical datatype of stacks, and a further application is sketched