Figure 2.

Look-ahead strategy. Two reactions leading current state ${\mathit{x}}_{i-1}$ to next state ${\mathit{x}}_i$ are shown in dashed lines (blue and pink). All possible look-ahead paths of length κ = 2 for both reactions from two different next states ${\mathit{x}}_i$ are illustrated in solid blue and pink lines. State B is the initial state, and D is the target state. The thickness of lines indicates reaction rates. The color of circles at the end state of each path indicates moving forward (green, ${\mathcal{P}}_F$), backward (red, ${\mathcal{P}}_B$), and non-moving (yellow, ${\mathcal{P}}_N$).