Visualise Undrawable Euler Diagrams

Given a group of overlapping sets, it is not always possible to represent it with Euler diagrams. Euler diagram characteristics might collide with the sets relationships to depict, making it impossible to outline a correct draw. In order to be able to show a greater class of instances, Euler diagrams have been extended allowing more general patterns, but so far all the most common definitions cannot represent all the possible connection between sets.We aim to introduce methods and constructions to produce a clear representation, as close as possible to Euler diagrams, even for sets that are not formally drawable in that way. We investigate on the reasons that make a diagram undrawable, in order to evaluate how and when to apply the mentioned structures, and to give the foundations necessary to design algorithms for this purpose.