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Efficient parameterized algorithms by number of reconfiguration steps

Determine whether the Layered Connectivity Shortest Reconfiguration decision problem—given two always-connected temporal graphs G1 and G2 and an integer l, decide if there is a valid reconfiguration sequence of length at most l—admits efficient parameterized algorithms when parameterized by l (the number of reconfiguration steps), and, if so, construct such algorithms.

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Background

The paper introduces the Layered Connectivity Reconfiguration problem on always-connected temporal graphs and provides a polynomial-time algorithm for deciding reconfigurability and constructing a valid sequence of edge relabelings, as well as an NP-hardness result for finding a shortest reconfiguration sequence via a reduction from Vertex Cover.

In the conclusion, the authors highlight further directions, including parameterized variants. A specific open question asks whether efficient algorithms can be obtained by parameterizing by the number of reconfiguration steps, which directly targets the parameterized complexity of the length-bounded decision problem (Layered Connectivity Shortest Reconfiguration) defined in the paper.

References

Beyond these results, several open questions remain. Finally, exploring parameterized variants could give further insight into the problem's complexity. For example, can we get efficient algorithms by parameterizing by the number of reconfiguration steps?

Temporal Graph Reconfiguration for Always-Connected Graphs (2510.15593 - Sievers et al., 17 Oct 2025) in Conclusion