Fixed-query logarithmic-power gap

Determine whether a fixed-query method can achieve a stochastic term with logarithmic power in the range $1\le p<3$, thereby improving on the $O(\sigma^2\log^3 N/N)$ stochastic terms of RAIN and RRSEG while respecting the lower-bound exclusion of every power $p<1$.

Background

The lower-bound corollary proves that no fixed-query method can uniformly guarantee an expected squared residual of order O(L2D2/N2+σ2log⁡pN/N)O(L^2D^2/N^2+\sigma^2\log^pN/N) for any p<1p<1. RRSEG attains the optimal deterministic O(1/N2)O(1/N^2) term but has stochastic logarithmic power p=3p=3, while RAIN has the same logarithmic power and uses an increasing number of oracle queries per iteration. Consequently, the interval between the lower-bound threshold and the currently achieved upper bound remains unresolved.

References

Corollary~\ref{lb:cor:fixed-query} leaves the range $1\le p<3$ open: it rules out every logarithmic power $p<1$, whereas the near-optimal bounds of both RAIN and RRSEG have stochastic logarithmic power $p=3$; RRSEG achieves this dependence with a fixed number of oracle queries per iteration.

— Accelerated Algorithms for Stochastic Monotone Inclusions with Fixed Queries  (2609.35631 - Lee et al., 28 Sep 2026) in Section 1, immediately following Corollary \ref{lb:cor:fixed-query}; also stated in Section 3, paragraph following Corollary \ref{rr:cor:explicit}