Perfect phylogenies via the Minimum Uncovering Branching problem: efficiently solvable cases

Fuente: arXiv
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Main Authors: Baghirova, Narmina, Galby, Esther, Milanič, Martin
Format: Preprint
Published: 2025
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author Baghirova, Narmina
Galby, Esther
Milanič, Martin
author_facet Baghirova, Narmina
Galby, Esther
Milanič, Martin
contents In this paper, we present new efficiently solvable cases of the Minimum Uncovering Branching problem, an optimization problem with applications in cancer genomics introduced by Hujdurović, Husić, Milanič, Rizzi, and Tomescu in 2018. The problem involves a family of finite sets, and the goal is to map each non-maximal set to exactly one set that contains it, minimizing the sum of uncovered elements across all sets in the family. Hujdurović et al. formulated the problem in terms of branchings of the digraph formed by the proper set inclusion relation on the input sets and studied the problem complexity based on properties of the corresponding partially ordered set, in particular, with respect to its height and width, defined respectively as the maximum cardinality of a chain and an antichain. They showed that the problem is APX-complete for instances of bounded height and that a constant-factor approximation algorithm exists for instances of bounded width, but left the exact complexity for bounded-width instances open. In this paper, we answer this question by proving that the problem is solvable in polynomial time. We derive this result by examining the structural properties of optimal solutions and reducing the problem to computing maximum matchings in bipartite graphs and maximum weight antichains in partially ordered sets. We also introduce a new polynomially computable lower bound and identify another condition for polynomial-time solvability.
format Preprint
id arxiv_https___arxiv_org_abs_2506_18578
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Perfect phylogenies via the Minimum Uncovering Branching problem: efficiently solvable cases
Baghirova, Narmina
Galby, Esther
Milanič, Martin
Discrete Mathematics
Data Structures and Algorithms
Combinatorics
Populations and Evolution
05C85 (Primary), 05C20, 05C90, 06A07, 92D10 (Secondary)
In this paper, we present new efficiently solvable cases of the Minimum Uncovering Branching problem, an optimization problem with applications in cancer genomics introduced by Hujdurović, Husić, Milanič, Rizzi, and Tomescu in 2018. The problem involves a family of finite sets, and the goal is to map each non-maximal set to exactly one set that contains it, minimizing the sum of uncovered elements across all sets in the family. Hujdurović et al. formulated the problem in terms of branchings of the digraph formed by the proper set inclusion relation on the input sets and studied the problem complexity based on properties of the corresponding partially ordered set, in particular, with respect to its height and width, defined respectively as the maximum cardinality of a chain and an antichain. They showed that the problem is APX-complete for instances of bounded height and that a constant-factor approximation algorithm exists for instances of bounded width, but left the exact complexity for bounded-width instances open. In this paper, we answer this question by proving that the problem is solvable in polynomial time. We derive this result by examining the structural properties of optimal solutions and reducing the problem to computing maximum matchings in bipartite graphs and maximum weight antichains in partially ordered sets. We also introduce a new polynomially computable lower bound and identify another condition for polynomial-time solvability.
title Perfect phylogenies via the Minimum Uncovering Branching problem: efficiently solvable cases
topic Discrete Mathematics
Data Structures and Algorithms
Combinatorics
Populations and Evolution
05C85 (Primary), 05C20, 05C90, 06A07, 92D10 (Secondary)
url https://arxiv.org/abs/2506.18578