Parameter-free first-order gradient minimization in ℓp geometry

Fix 1<p<∞1<p<\infty and let q=p/(p−1)q=p/(p-1). Given a first-order local value--gradient oracle for an objective f:Rn→Rf:\mathbb{R}^n\to\mathbb{R} whose gradient is LL-Lipschitz from (Rn,∥⋅∥p)(\mathbb{R}^n,\|\cdot\|_p) to (Rn,∥⋅∥q)(\mathbb{R}^n,\|\cdot\|_q), an initial point x0x_0 with a solution x∗x^* satisfying ∥x0−x∗∥p≤R\|x_0-x^*\|_p\le R, and a target ε>0\varepsilon>0, determine whether there is a parameter-free algorithm that does not know LL, RR, or f∗f^* and returns a queried point x^\widehat{x} satisfying ∥∇f(x^)∥q≤ε\|\nabla f(\widehat{x})\|_q\le\varepsilon, with dimension-free oracle complexity governed by K‾=max⁡{1,LR/ε}\overline K=\max\{1,LR/\varepsilon\}. Under a nondegenerate secant initialization, the claimed bounds are Op(K‾1/2)O_p(\overline K^{1/2}) post-initialization queries for 1<p≤21<p\le2 and Op(K‾p/(p+2))O_p(\overline K^{p/(p+2)}) for p>2p>2, together with an additive calibration cost Op(log⁡(e+L/M0))O_p(\log(e+L/M_0)).

References

Primary source

arXiv

Progress summary

Refreshed
Claimed progress

A new preprint claims a parameter-free optimization method works in every finite-dimensional geometry measured by an ellpell_p norm, but the claim has not been independently checked.

The problem asks whether first-order optimization can minimize gradients without knowing key scale parameters in general ellpell_p geometry for fixed 1<p<∞1<p<\infty. The latest source presents a proposed method extending parameter-free guarantees beyond previously unresolved general-ℓp\ell_p settings.

Known results

  • Diakonikolas and Guzmán, version dated February 15, 2023: complementary minimization in general normed spaces, including a nearly optimal standard-ℓ1\ell_1 method measured in the ℓ∞\ell_\infty norm, but not the claimed parameter-free all-ℓp\ell_p result.
  • A related paper claims parameter-free gradient minimization over Rn\mathbb{R}^n, without establishing the specific general-ℓp\ell_p problem.

August 27, 2026 proposed all-ℓp\ell_p method

An arXiv entry claims an adaptive method for every fixed 1<p<∞1<p<\infty, without prior knowledge of smoothness, initial-distance, or optimum-value scales. This is claimed progress, not a verified resolution: the retrieved abstract is truncated, leaving the exact assumptions and complexity guarantees unchecked.

Current status (as of August 2026): A preprint claims progress for every fixed 1<p<∞1<p<\infty, but its assumptions and guarantees remain to be verified; no independently confirmed complete solution was found.

Sources

Solutions 0

No solutions have been posted yet.