Determine whether a bound of 2^n suffices for optimal strategy length

Determine whether every water transport problem on an n-vertex graph admits an optimal strategy of length at most 2^n.

Background

The paper studies the water transport problem in the connected-set averaging model, where a strategy consists of averaging the weights on connected vertex sets and seeks to maximize the final weight at a designated target vertex. Prior work had established finite attainment of an optimum but had not supplied a uniform strategy-length bound depending only on the number of vertices.

The paper proves a substantially larger uniform bound of n{(2+o(1))n}. Consequently, the specifically proposed bound 2n remains unresolved in the text: the authors establish computable uniform boundedness but do not determine whether the sharper exponential bound 2n always suffices.

References

Gollin et al.Section~6 asked whether such a computable bound exists, and in particular whether $2{|V|}$ always suffices Question~6.1.

— A Uniform Bound on Optimal Strategy Length in Water Transport Problem  (2609.30932 - Tao et al., 25 Sep 2026) in Section 1, Introduction