Positiveness of a Tree Graph Cut
With a graph cutted and divided in two parts, you can then close a loop with your line cut. The loop should encompass the one part entirely (no matter which one of the two).
Is the arrow of the branch you cutted inside your loop?
- If yes: all the cutted strings whose arrow are inside the loop will be positive. Otherwise negative.
- If no: all the cutted strings whose arrow are inside the loop will be negative. Otherwise positive.
The branch cutted will be always positive.