example, for handling indirect attacks and defenses we have prudent and careful semantics [@inproc:careful; @inproc:prudent]. For the problem of even and odd attack cycles we can resort to some of the SCC–recursive semantics [@BaroniGG05a], while for treatment of self attackers, sustainable and tolerant semantics were developed [@Bodanza2009]. Introducing a new type of relation, such as support, creates additional problems.

The most controversial issue in the bipolar setting concerns the support cycles and is handled differently from formalism to formalism. Among the best known structures are the Bipolar Argumentation Frameworks (BAFs for short) [@incoll:bipolar; @article:newbaf], Argumentation Frameworks with Necessities (AFNs) [@incoll:newafn] and Evidential Argumentation Systems (EASs) [@inproc:eas]. While AFNs and EASs discard support cycles, BAFs do not make such restrictions. In ADFs cycles are permitted unless the intuition of a given semantics is clearly against it, for example in stable and grounded cases. This variety is not an error in any of the structures; it is caused by the fact that, in a setting that allows more types of relations, a standard Dung semantics can be extended in several ways. Moreover, since one can find arguments both for and against any of the cycle treatments, lack of consensus as to what 