English

Parameterized Complexity of Biclique Contraction and Balanced Biclique Contraction

Data Structures and Algorithms 2026-01-15 v2 Computational Complexity

Abstract

In this work, we initiate the complexity study of Biclique Contraction and Balanced Biclique Contraction. In these problems, given as input a graph G and an integer k, the objective is to determine whether one can contract at most k edges in G to obtain a biclique and a balanced biclique, respectively. We first prove that these problems are NP-complete even when the input graph is bipartite. Next, we study the parameterized complexity of these problems and show that they admit single exponential-time FPT algorithms when parameterized by the number k of edge contractions. Then, we show that Balanced Biclique Contraction admits a quadratic vertex kernel while Biclique Contraction does not admit any polynomial compression (or kernel) under standard complexity-theoretic assumptions. We also give faster FPT algorithms for contraction to restricted bicliques.

Keywords

Cite

@article{arxiv.2307.10607,
  title  = {Parameterized Complexity of Biclique Contraction and Balanced Biclique Contraction},
  author = {R. Krithika and V. K. Kutty Malu and Roohani Sharma and Prafullkumar Tale},
  journal= {arXiv preprint arXiv:2307.10607},
  year   = {2026}
}