Cycle isomorphism

Cycle isomorphism --- циклический изоморфизм.

A bijection [math]\displaystyle{ f }[/math] between the vertex sets [math]\displaystyle{ V_{1} }[/math] and [math]\displaystyle{ V_{2} }[/math] of two sigraphs [math]\displaystyle{ S_{1} }[/math] and [math]\displaystyle{ S_{2} }[/math], respectively, is called f cycle isomorphism (or weak isomorphism) between [math]\displaystyle{ S_{1} }[/math] and [math]\displaystyle{ S_{2} }[/math] if [math]\displaystyle{ f }[/math] preserves both vertex adjacen\-cies and cycle signs of [math]\displaystyle{ S_{1} }[/math] and [math]\displaystyle{ S_{2} }[/math].