Figure 1
From: A minimum-labeling approach for reconstructing protein networks across multiple conditions
The optimal MKL solution for α = 0.5 is neither the union of label-specific Steiner trees nor a subgraph of it. In this instance k = 2, T1 = {x, y} and T2 = {y, z}. The optimal Steiner trees for T1 and T2 are composed of the red (dashed) and blue (solid) edges, respectively. The best MKL solution that uses only edges of the union can be achieved by pushing label 1 over the red edges and 2 over the blue edges, resulting in 14 labels and 14 edges. In contrast, the optimal solution, whose labels appear on top of the figure, contains the blue and green (waved) edges, spanning 15 labels and 9 edges.