Rodriguez, M. L.Gea, M.Gutiérrez, F. L.2015-11-112015-11-1119991017-4656http://dx.doi.org/10.2312/egs.19991047Modern interactive systems are oriented towards information management in a graphical environment. Formal specification techniques [1] help designers to describe systems, focusing on the relevant aspects of the interaction model. We analyse here a new way of describing the specifications of a directmanipulation system and we propose an extension of this concept to cover the specifications of a system based on spatial relationships.