Figure 1

Star transformation. (a) A star with the center v in $\hat{G}$ and k ≥ 3 edges. Here ei = {v, w _i } for i = 1, 2, . . . , k. (b) A simplified representation of edges (empty, single and double) that will be used through the rest of this work. The notation ≠ ⊤ denotes that the label is a non-root node from S.