A Tight Regret Analysis of Non-Parametric Repeated Contextual Brokerage

Fuente: arXiv
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Autori principali: Bachoc, François, Cesari, Tommaso, Colomboni, Roberto
Natura: Preprint
Pubblicazione: 2025
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author Bachoc, François
Cesari, Tommaso
Colomboni, Roberto
author_facet Bachoc, François
Cesari, Tommaso
Colomboni, Roberto
contents We study a contextual version of the repeated brokerage problem. In each interaction, two traders with private valuations for an item seek to buy or sell based on the learner's-a broker-proposed price, which is informed by some contextual information. The broker's goal is to maximize the traders' net utility-also known as the gain from trade-by minimizing regret compared to an oracle with perfect knowledge of traders' valuation distributions. We assume that traders' valuations are zero-mean perturbations of the unknown item's current market value-which can change arbitrarily from one interaction to the next-and that similar contexts will correspond to similar market prices. We analyze two feedback settings: full-feedback, where after each interaction the traders' valuations are revealed to the broker, and limited-feedback, where only transaction attempts are revealed. For both feedback types, we propose algorithms achieving tight regret bounds. We further strengthen our performance guarantees by providing a tight 1/2-approximation result showing that the oracle that knows the traders' valuation distributions achieves at least 1/2 of the gain from trade of the omniscient oracle that knows in advance the actual realized traders' valuations.
format Preprint
id arxiv_https___arxiv_org_abs_2503_02646
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A Tight Regret Analysis of Non-Parametric Repeated Contextual Brokerage
Bachoc, François
Cesari, Tommaso
Colomboni, Roberto
Machine Learning
Computer Science and Game Theory
We study a contextual version of the repeated brokerage problem. In each interaction, two traders with private valuations for an item seek to buy or sell based on the learner's-a broker-proposed price, which is informed by some contextual information. The broker's goal is to maximize the traders' net utility-also known as the gain from trade-by minimizing regret compared to an oracle with perfect knowledge of traders' valuation distributions. We assume that traders' valuations are zero-mean perturbations of the unknown item's current market value-which can change arbitrarily from one interaction to the next-and that similar contexts will correspond to similar market prices. We analyze two feedback settings: full-feedback, where after each interaction the traders' valuations are revealed to the broker, and limited-feedback, where only transaction attempts are revealed. For both feedback types, we propose algorithms achieving tight regret bounds. We further strengthen our performance guarantees by providing a tight 1/2-approximation result showing that the oracle that knows the traders' valuation distributions achieves at least 1/2 of the gain from trade of the omniscient oracle that knows in advance the actual realized traders' valuations.
title A Tight Regret Analysis of Non-Parametric Repeated Contextual Brokerage
topic Machine Learning
Computer Science and Game Theory
url https://arxiv.org/abs/2503.02646