Demonic composition
Introduction In mathematics, '''demonic composition''' is an operation on binary relations that is similar to the ordinary composition of relations but is robust to refinement of the relations into (partial) functions or injective relations.Unlike ordinary composition of relations, demonic composition is not associative.
Definition Suppose  is a binary relation between  and  and  is a relation between  and   Their ''''''  is a relation between  and   Its graph is defined asConversely, their ''''''  is defined by
References * .