When you want to pick something... Methodology 2:Good properties often happen at extremal points. Let's consider to pick the currently "best"one. The u with the min dist(u) u∈V-R Recall that now dist(u)is only an upper bound of l(s,u) It corresponds to a path we've found so far,but there may be better routes found later. 28When you want to pick something… ◼ Methodology 2: Good properties often happen at extremal points. ◼ Let’s consider to pick the currently “best” one. ❑ The 𝑢 with the min 𝑢∈𝑉−𝑅 𝑑𝑖𝑠𝑡 𝑢 ◼ Recall that now 𝑑𝑖𝑠𝑡(𝑢) is only an upper bound of 𝑙(𝑠, 𝑢) ❑ It corresponds to a path we’ve found so far, but there may be better routes found later. 28