F-Ray

[math]\displaystyle{ F }[/math]-Ray --- [math]\displaystyle{ F }[/math]-луч.

Let [math]\displaystyle{ F }[/math] be a numbering of a cf-graph [math]\displaystyle{ G }[/math] and [math]\displaystyle{ A }[/math] be a ray of [math]\displaystyle{ G }[/math]. [math]\displaystyle{ A }[/math] is called [math]\displaystyle{ F }[/math]ray if it contains only [math]\displaystyle{ F }[/math]-arcs.