Figure 4

Example of uncovered edges in peripheral and main components. (a) Initially deduced edges (E _ide ). (b) Essential edges (E _es ). Non-essential edges are dotted. (c) Uncovered edges (E _ucv ). Because all non-essential edges cannot be covered by essential edges, the non-essential edges are called uncovered edges (E _ucv ). (d) Uncovered edges in peripheral components (gray-dotted). (B, D) and (B, E) are uncovered edges in peripheral components because (B, E) does not explain any other edges in E _ucv with an edge in E _ide , and (B, D) does not explain any other edges in E _ucv except (B, E) with an edge in E _ide . (A, C) and (B, C) are uncovered edges in main components. If edges in a MEGN cover (A, C) and (B, C), the edges also cover (B, D) and (B, E). (B, D) and (B, E) cover no edges except themselves. Thus, (B, D) and (B, E) are not included in the MEGNs.