Near-linear one-to-all fastest durations with uniform zero delay

Establish whether, for an undirected interval temporal graph with uniform zero delay, an algorithm can compute in $\widetilde{\mathcal O}(M)$ time the durations of fastest temporal paths from a specified source vertex to every target vertex.

Background

The paper presents a O~(M)\widetilde{\mathcal O}(M) algorithm for computing a fastest temporal path between one specified source-target pair when all delays are zero. The conclusion asks whether a comparable near-linear running time is possible for the one-to-all problem, in which a single source is fixed and fastest-path durations to all target vertices must be computed. The authors note that their profile algorithm cannot directly provide one-to-all profiles in the same time because an individual profile may have size Ω(M)\Omega(M), although it can produce all profiles in O~(nM)\widetilde{\mathcal O}(nM) time.

References

In the case of uniform zero delay, can we similarly hope to find an $\widetilde{\cal O}(M)$ algorithm for computing one-to-all fastest durations, i.e., given a source vertex $s$, an algorithm that computes the duration of a fastest temporal path from $s$ to each possible target vertex $t$?

On the Complexity of Computing a Fastest Temporal Path in Interval Temporal Graphs  (2501.11380 - Aubian et al., 20 Jan 2025) in Section 5, Conclusion