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Surpass the one-half approximation barrier for online block packing

Establish whether there exists any online algorithm—either fractional or integral—for the online block packing problem with multi-dimensional resource capacities and time-discounted (quasi-patient) transaction values that achieves an approximation ratio strictly greater than 1/2 with respect to the offline optimal social welfare; equivalently, demonstrate a (1/2+ε0)-approximation for some fixed ε0>0, potentially highlighting the limits of myopic reasoning in this setting.

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Background

The paper proves that a greedy fractional algorithm achieves at least half of the offline optimal social welfare, and shows matching lower bounds for broad classes of myopically-reasonable online algorithms that approach the 1/2 barrier as the number of dimensions grows. This leaves open whether any (possibly non-myopic) online strategy can strictly beat 1/2.

A result exceeding 1/2 would demonstrate that myopic block-by-block optimization is fundamentally suboptimal and that foresight or more sophisticated online decision rules are necessary to improve welfare beyond this threshold.

References

Can any online algorithm—fractional or integral—guarantee strictly more than one half of the offline optimum? Establishing a (\tfrac12+\varepsilon_0)-approximation for any fixed \varepsilon_0>0 would demonstrate the limitations of myopic reasoning for this online problem. All three challenges remain open even in the fully patient regime (\rho_i=0).

Online Block Packing (2507.12357 - Eliezer et al., 16 Jul 2025) in Subsubsection “Surpassing the 1/2 barrier,” Open Problems and Future Work