Abstract
Perturbed graphic matroids are binary matroids that can be obtained from a graphic matroid by adding a noise of small rank. More precisely, an rrank perturbed graphic matroid M is a binary matroid that can be represented in the form I +P, where I is the incidence matrix of some graph and P is a binary matrix of rank at most r. Such matroids naturally appear in a number of theoretical and applied settings. The main motivation behind our work is an attempt to understand which parameterized algorithms for various problems on graphs could be lifted to perturbed graphic matroids.
We study the parameterized complexity of a natural generalization (for matroids) of the following fundamental problems on graphs: Steiner Tree and Multiway Cut. In this generalization, called the Space Cover problem, we are given a binary matroid M with a ground set E, a set of terminals T subseteq E, and a nonnegative integer k. The task is to decide whether T can be spanned by a subset of E \ T of size at most k.
We prove that on graphic matroid perturbations, for every fixed r, Space Cover is fixedparameter tractable parameterized by k. On the other hand, the problem becomes W[1]hard when parameterized by r+k+T and it is NPcomplete for r <= 2 and T<= 2.
On cographic matroids, that are the duals of graphic matroids, Space Cover generalizes another fundamental and wellstudied problem, namely Multiway Cut. We show that on the duals of perturbed graphic matroids the Space Cover problem is fixedparameter tractable parameterized by r+k.
BibTeX  Entry
@InProceedings{fomin_et_al:LIPIcs:2019:10635,
author = {Fedor V. Fomin and Petr A. Golovach and Daniel Lokshtanov and Saket Saurabh and Meirav Zehavi},
title = {{Covering Vectors by Spaces in Perturbed Graphic Matroids and Their Duals}},
booktitle = {46th International Colloquium on Automata, Languages, and Programming (ICALP 2019)},
pages = {59:159:13},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {9783959771092},
ISSN = {18688969},
year = {2019},
volume = {132},
editor = {Christel Baier and Ioannis Chatzigiannakis and Paola Flocchini and Stefano Leonardi},
publisher = {Schloss DagstuhlLeibnizZentrum fuer Informatik},
address = {Dagstuhl, Germany},
URL = {http://drops.dagstuhl.de/opus/volltexte/2019/10635},
URN = {urn:nbn:de:0030drops106351},
doi = {10.4230/LIPIcs.ICALP.2019.59},
annote = {Keywords: Binary matroids, perturbed graphic matroids, spanning set, parameterized complexity}
}
Keywords: 

Binary matroids, perturbed graphic matroids, spanning set, parameterized complexity 
Collection: 

46th International Colloquium on Automata, Languages, and Programming (ICALP 2019) 
Issue Date: 

2019 
Date of publication: 

04.07.2019 