English

Inverse matroid optimization under subset constraints

Data Structures and Algorithms 2025-07-03 v2 Discrete Mathematics

Abstract

In the Inverse Matroid problem, we are given a matroid, a fixed basis BB, and an initial weight function, and the goal is to minimally modify the weights -- measured by some function -- so that BB becomes a maximum-weight basis. The problem arises naturally in settings where one wishes to explain or enforce a given solution by minimally perturbing the input. We extend this classical problem by replacing the fixed basis with a subset S0S_0 of the ground set and imposing various structural constraints on the set of maximum-weight bases relative to S0S_0. Specifically, we study six variants: (A) Inverse Matroid Exists, where S0S_0 must contain at least one maximum-weight basis; (B) Inverse Matroid All, where all bases contained in S0S_0 are maximum-weight; and (C) Inverse Matroid Only, where S0S_0 contains exactly the maximum-weight bases, along with their natural negated counterparts. For all variants, we develop combinatorial polynomial-time algorithms under the \ell_\infty-norm. A key ingredient is a refined min-max theorem for Inverse Matroid under the \ell_\infty-norm, which enables simpler and faster algorithms than previous approaches and may be of independent combinatorial interest. Our work significantly broadens the range of inverse optimization problems on matroids that can be solved efficiently, especially those that constrain the structure of optimal solutions through subset inclusion or exclusion.

Keywords

Cite

@article{arxiv.2507.00930,
  title  = {Inverse matroid optimization under subset constraints},
  author = {Kristóf Bérczi and Lydia Mirabel Mendoza-Cadena and José Soto},
  journal= {arXiv preprint arXiv:2507.00930},
  year   = {2025}
}

Comments

20 pages

R2 v1 2026-07-01T03:41:54.996Z