Preprint
Parameter-free Dynamic Regret: Time-varying Movement Costs, Delayed Feedback, and Memory
ArXiv.org
Cornell University
02/06/2026
DOI: 10.48550/arxiv.2602.06902
Abstract
In this paper, we study dynamic regret in unconstrained online convex optimization (OCO) with movement costs. Specifically, we generalize the standard setting by allowing the movement cost coefficientsλ_(t)to vary arbitrarily over time. Our main contribution is a novel algorithm that establishes the first comparator-adaptive dynamic regret bound for this setting, guaranteeing\widetilde{𝓞}{(}{√(̅1̅+̅P̅_̅(̅T̅)̅)̅(̅T̅+̅∑̅_̅(̅t̅)̅ ̅λ̅_̅(̅t̅)̅)̅})regret, whereP_(T)is the path length of the comparator sequence overTrounds. This recovers the optimal guarantees for both static and dynamic regret in standard OCO as a special case whereλ_(t)=0for all rounds. To demonstrate the versatility of our results, we consider two applications: OCO with delayed feedback and OCO with time-varying memory. We show that both problems can be translated into time-varying movement costs, establishing a novel reduction specifically for the delayed feedback setting that is of independent interest. A crucial observation is that the first-order dependence on movement costs in our regret bound plays a key role in enabling optimal comparator-adaptive dynamic regret guarantees in both settings.
Details
- Title: Subtitle
- Parameter-free Dynamic Regret: Time-varying Movement Costs, Delayed Feedback, and Memory
- Creators
- Emmanuel EspositoAndrew Jacobsen - Politecnico di MilanoHao QiuMengxiao Zhang
- Resource Type
- Preprint
- Publication Details
- ArXiv.org
- DOI
- 10.48550/arxiv.2602.06902
- ISSN
- 2331-8422
- Publisher
- Cornell University; Ithaca, New York
- Language
- English
- Date posted
- 02/06/2026
- Academic Unit
- Business Analytics
- Record Identifier
- 9985139311702771
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