Converse digraph

Converse digraph --- обратный орграф.

Let [math]\displaystyle{ D }[/math] be a digraph. The converse of [math]\displaystyle{ D }[/math], denoted [math]\displaystyle{ D' }[/math], is a digraph obtained from [math]\displaystyle{ D }[/math] by reversing the direction of each arc of [math]\displaystyle{ D }[/math]. A digraph is called self-converse if it is isomorphic to its converse.