arXiv subjects

Omar Bennouna

Publications and source records attributed to Omar Bennouna.

4 recordsLinked to original sources

arXiv2026

The Geometry of Linear Program Compression: An Exact Characterization and Learning Algorithm

We study how much a linear program (LP) can be compressed when solved repeatedly, given prior knowledge about its objective function. Existing data-driven projection methods learn low-dimensional surrogate LPs with approximate objective-value guarantees, but cannot provably identify the optimal projection for a prescribed compression budget. We instead ask a sharper question: how far can an LP be compressed into a lower-dimensional equivalent while \emph{exactly} preserving optimality, enabling faster repeated solves with no loss in solution quality? We provide an exact geometric characterization of such compressed LPs, together with a tractable sample-based learning algorithm that comes with fast-rate guarantees: the compressed LP recovers the optimal solution of an unseen instance with probability at least $1-\widetilde O(d^\star/n)$, where $d^\star$ is the dimension of the decision-relevant subspace, and $n$ is the number of available historical LP samples. This $1/n$ dependence is sharper than the $\widetilde O(1/\sqrt n)$ uniform-convergence rates of approximate projection methods. Our framework further exposes a tunable tradeoff between the dimension of the compressed LP and the probability of recovering the optimal solution, allowing the user to trade compression for accuracy.

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arXiv2026

Data Informativeness in Linear Optimization under Uncertainty

We study the problem of determining what data is required to solve a decision-making task when only partial information about the state of the world is available. Focusing on linear programs, we introduce a decision-focused notion of data informativeness that formalizes when a data set is sufficient to recover the optimal decision. Our notion abstracts away the notion of estimators (how data is used): it depends solely on the structure of the optimization task and the uncertainty. Our main result provides a geometric characterization of data sufficiency: a data set is sufficient if and only if, together with prior knowledge, it captures all cost directions that can change the optimal solution, given the task structure and the uncertainty set. Building on our characterization, we develop a tractable algorithm to determine minimal sufficient data sets under general data collection constraints. Taken together, our work introduces a principled framework for task-aware data collection. We demonstrate the approach in two applications: selecting where to conduct field experiments to inform infrastructure design and choosing which candidates to interview in order to make an optimal hiring decision. Our results illustrate that small, carefully selected data sets often suffice to determine the optimal decisions.

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arXiv2025

What Data Enables Optimal Decisions? An Exact Characterization for Linear Optimization

We study the fundamental question of how informative a dataset is for solving a given decision-making task. In our setting, the dataset provides partial information about unknown parameters that influence task outcomes. Focusing on linear programs, we characterize when a dataset is sufficient to recover an optimal decision, given an uncertainty set on the cost vector. Our main contribution is a sharp geometric characterization that identifies the directions of the cost vector that matter for optimality, relative to the task constraints and uncertainty set. We further develop a practical algorithm that, for a given task, constructs a minimal or least-costly sufficient dataset. Our results reveal that small, well-chosen datasets can often fully determine optimal decisions -- offering a principled foundation for task-aware data selection.

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arXiv2025

Addressing misspecification in contextual optimization

We study a linear contextual optimization problem where a decision maker has access to historical data and contextual features to learn a cost prediction model aimed at minimizing decision error. We adopt the predict-then-optimize framework for this analysis. Given that perfect model alignment with reality is often unrealistic in practice, we focus on scenarios where the chosen hypothesis set is misspecified. In this context, it remains unclear whether current contextual optimization approaches can effectively address such model misspecification. In this paper, we present a novel integrated learning and optimization approach designed to tackle model misspecification in contextual optimization. This approach offers theoretical generalizability, tractability, and optimality guarantees, along with strong practical performance. Our method involves minimizing a tractable surrogate loss that aligns with the performance value from cost vector predictions, regardless of whether the model is misspecified, and can be optimized in reasonable time. To our knowledge, no previous work has provided an approach with such guarantees in the context of model misspecification.

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