A simple Path-based LP Relaxation for Directed Steiner Tree

Fuente: arXiv
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Hauptverfasser: Pashkovich, Kanstantsin, Pozzi, Marta, Sanità, Laura
Format: Preprint
Veröffentlicht: 2026
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author Pashkovich, Kanstantsin
Pozzi, Marta
Sanità, Laura
author_facet Pashkovich, Kanstantsin
Pozzi, Marta
Sanità, Laura
contents We study the Directed Steiner Tree (DST) problem in layered graphs through a simple path-based linear programming relaxation. This relaxation achieves an integrality gap of O(l log k), where k is the number of terminals and l is the number of layers, which matches the best known bounds for DST previously obtained via lift-and-project hierarchies. Our formulation bypasses hierarchy machinery, offering a more transparent route to the state-of-the-art bound, and it can be exploited to provide an alternative simpler proof that O(l) rounds of the Sherali-Adams hierarchy suffice for reducing the integrality gap on layered instances of DST.
format Preprint
id arxiv_https___arxiv_org_abs_2603_02825
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle A simple Path-based LP Relaxation for Directed Steiner Tree
Pashkovich, Kanstantsin
Pozzi, Marta
Sanità, Laura
Data Structures and Algorithms
Primary: 90C27 Secondary: 68W25, 90C05
We study the Directed Steiner Tree (DST) problem in layered graphs through a simple path-based linear programming relaxation. This relaxation achieves an integrality gap of O(l log k), where k is the number of terminals and l is the number of layers, which matches the best known bounds for DST previously obtained via lift-and-project hierarchies. Our formulation bypasses hierarchy machinery, offering a more transparent route to the state-of-the-art bound, and it can be exploited to provide an alternative simpler proof that O(l) rounds of the Sherali-Adams hierarchy suffice for reducing the integrality gap on layered instances of DST.
title A simple Path-based LP Relaxation for Directed Steiner Tree
topic Data Structures and Algorithms
Primary: 90C27 Secondary: 68W25, 90C05
url https://arxiv.org/abs/2603.02825