# algorithms – Optimal TSP path with connection and link

I just wanted a little clarification on the image above. I understand the general idea of ​​building a tree in DFS order and stopping once you run into a higher number than you had before. For example, when the path value becomes $$14$$ or $$inf$$ the algorithm stops because there was already a value path $$11$$. But, I'm quite confused as to where these numbers came from (the lower cost limits). For example, the path from the top $$A$$ at the top $$B$$ has a length $$1$$, but in the tree, the path of $$A$$ at $$B$$ has a lower limit of $$10$$.

So, I would greatly appreciate if someone could let me know where the numbers come from in the branches and links search tree!