Dual hypergraph

Dual hypergraph --- двойственный гиперграф.

A dual hypergraph [math]\displaystyle{ {\mathcal H}^{\ast} }[/math] has [math]\displaystyle{ {\mathcal H} }[/math] as its vertex set and [math]\displaystyle{ \{e \in {\mathcal H}; \; v \in e\} \; (v \in V) }[/math] as its edges.