Kernels for deletion to classes of acyclic digraphs

Akanksha Agrawal, Saket Saurabh, Roohani Sharma, Meirav Zehavi

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Given a digraph D and an integer k, DIRECTED FEEDBACK VERTEX SET (DFVS) asks whether there exists a set of vertices S of size at most k such that F=D∖S is DAG. Mnich and van Leeuwen [STACS 2016 ] considered the kernelization complexity of DFVS with an additional restriction on F, namely that F must be an out-forest (OUT-FOREST VERTEX DELETION SET), an out-tree (OUT-TREE VERTEX DELETION SET), or a (directed) pumpkin (PUMPKIN VERTEX DELETION SET). Their objective was to shed light on the kernelization complexity of DFVS, a well-known open problem in Parameterized Complexity. We improve the kernel sizes of OUT-FOREST VERTEX DELETION SET from O(k3) to O(k2) and of PUMPKIN VERTEX DELETION SET from O(k18) to O(k3). We also prove that the former kernel size is tight under certain complexity theoretic assumptions.

Original languageEnglish
Pages (from-to)9-21
Number of pages13
JournalJournal of Computer and System Sciences
StatePublished - 1 Mar 2018
Externally publishedYes


  • Kernelization
  • Out-forest
  • Parameterized complexity
  • Pumpkin

ASJC Scopus subject areas

  • Theoretical Computer Science
  • Computer Networks and Communications
  • Computational Theory and Mathematics
  • Applied Mathematics


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