On the NP-hardness of edge-deletion and -contraction problems

@article{Watanabe1983OnTN,
  title={On the NP-hardness of edge-deletion and -contraction problems},
  author={Toshimasa Watanabe and Tadashi Ae and Akira Nakamura},
  journal={Discrete Applied Mathematics},
  year={1983},
  volume={6},
  pages={63-78}
}
For a subset S={e;,,..., ej4} CEG (q = ISI), let G[S] denote the graph obtained from G by deleting ei,, . . . , eiq, and G(S) the graph obtained from G by contracting e;,, **., eiq (that is, the graph obtained from G[S] by coalescing two endnodes of ej into a single node for j= 1, . . . , q). For simplicity, we assume that, for each ei,, ond of its endnodes is coalesced into the other. Let VG(o) (EG(u), respectively) denote the set of all nodes adjacent to (all edges incident upon) o in G. Some… CONTINUE READING