Convexification of a Separable Function over a Polyhedral Ground Set

Fuente: arXiv
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Main Authors: Dey, Santanu S., Kocuk, Burak
Format: Preprint
Published: 2025
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author Dey, Santanu S.
Kocuk, Burak
author_facet Dey, Santanu S.
Kocuk, Burak
contents In this paper, we study the set $\mathcal{S}^κ= \{ (x,y)\in\mathcal{G}\times\mathbb{R}^n : y_j = x_j^κ, j=1,\dots,n\}$, where $κ> 1$ and the ground set $\mathcal{G}$ is a nonempty polytope contained in $[0,1]^n$. This nonconvex set is closely related to separable standard quadratic programming and appears as a substructure in potential-based network flow problems from gas and water networks. Our aim is to obtain the convex hull of $\mathcal{S}^κ$ or its tight outer-approximation for the special case when the ground set $\mathcal{G}$ is the standard simplex. We propose power cone, second-order cone and semidefinite programming relaxations for this purpose, which are further strengthened by the Reformulation-Linearization Technique and the Reformulation-Perspectification Technique. For $κ=2$, we obtain the convex hull of $\mathcal{S}^κ$ in the low-dimensional setting. For general $κ$, we give approximation guarantees for the power cone representable relaxation, the weakest relaxation we consider. We prove that this weakest relaxation is tight with probability one as $n\to\infty$ when a uniformly generated linear objective is optimized over it. Finally, we provide the results of our extensive computational experiments comparing the empirical strength of several conic programming relaxations that we propose.
format Preprint
id arxiv_https___arxiv_org_abs_2510_16595
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Convexification of a Separable Function over a Polyhedral Ground Set
Dey, Santanu S.
Kocuk, Burak
Optimization and Control
In this paper, we study the set $\mathcal{S}^κ= \{ (x,y)\in\mathcal{G}\times\mathbb{R}^n : y_j = x_j^κ, j=1,\dots,n\}$, where $κ> 1$ and the ground set $\mathcal{G}$ is a nonempty polytope contained in $[0,1]^n$. This nonconvex set is closely related to separable standard quadratic programming and appears as a substructure in potential-based network flow problems from gas and water networks. Our aim is to obtain the convex hull of $\mathcal{S}^κ$ or its tight outer-approximation for the special case when the ground set $\mathcal{G}$ is the standard simplex. We propose power cone, second-order cone and semidefinite programming relaxations for this purpose, which are further strengthened by the Reformulation-Linearization Technique and the Reformulation-Perspectification Technique. For $κ=2$, we obtain the convex hull of $\mathcal{S}^κ$ in the low-dimensional setting. For general $κ$, we give approximation guarantees for the power cone representable relaxation, the weakest relaxation we consider. We prove that this weakest relaxation is tight with probability one as $n\to\infty$ when a uniformly generated linear objective is optimized over it. Finally, we provide the results of our extensive computational experiments comparing the empirical strength of several conic programming relaxations that we propose.
title Convexification of a Separable Function over a Polyhedral Ground Set
topic Optimization and Control
url https://arxiv.org/abs/2510.16595