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Extending the SSBP lower bound from n updates to n^2 updates

Extend the conditional lower bound for incremental/decremental Single Source Bottleneck Paths (SSBP) on directed graphs—currently shown to require n^{2.5−o(1)} total update time over n updates under the Minimum-Witness Product hypothesis—to hold for n^2 updates.

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Background

The paper proves that, assuming the Minimum-Witness Product hypothesis, any partially dynamic SSBP algorithm requires n{2.5−o(1)} total update time over only n updates by reducing from min-witness product. This establishes a strong barrier for achieving faster partially dynamic SSBP in this regime.

However, the reduction and resulting lower bound presently apply to n updates; extending this conditional lower bound to n2 updates would match more typical dynamic settings and further solidify the hardness landscape for SSBP.

References

We leave as an interesting open question how to extend the following lower bound to $n2$ updates.

Fine-Grained Optimality of Partially Dynamic Shortest Paths and More (2407.09651 - Saha et al., 12 Jul 2024) in Section 4 (Bottleneck Paths), Conditional Lower Bounds, immediately before Theorem on SSBP lower bound from Minimum-Witness Product