Parameterized Temporal Exploration Problems

Authors Thomas Erlebach , Jakob T. Spooner

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Thomas Erlebach
  • Department of Computer Science, Durham University, UK
Jakob T. Spooner
  • School of Computing and Mathematical Sciences, University of Leicester, UK

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Thomas Erlebach and Jakob T. Spooner. Parameterized Temporal Exploration Problems. In 1st Symposium on Algorithmic Foundations of Dynamic Networks (SAND 2022). Leibniz International Proceedings in Informatics (LIPIcs), Volume 221, pp. 15:1-15:17, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2022)


In this paper we study the fixed-parameter tractability of the problem of deciding whether a given temporal graph 𝒢 admits a temporal walk that visits all vertices (temporal exploration) or, in some problem variants, a certain subset of the vertices. Formally, a temporal graph is a sequence 𝒢 = ⟨ G₁,..., G_L⟩ of graphs with V(G_t) = V(G) and E(G_t) ⊆ E(G) for all t ∈ [L] and some underlying graph G, and a temporal walk is a time-respecting sequence of edge-traversals. For the strict variant, in which edges must be traversed in strictly increasing timesteps, we give FPT algorithms for the problem of finding a temporal walk that visits a given set X of vertices, parameterized by |X|, and for the problem of finding a temporal walk that visits at least k distinct vertices in V, parameterized by k. For the non-strict variant, in which an arbitrary number of edges can be traversed in each timestep, we parameterize by the lifetime L of the input graph and provide an FPT algorithm for the temporal exploration problem. We also give additional FPT or W[2]-hardness results for further problem variants.

Subject Classification

ACM Subject Classification
  • Theory of computation → Graph algorithms analysis
  • Theory of computation → Fixed parameter tractability
  • Temporal graphs
  • fixed-parameter tractability
  • parameterized complexity


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