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Parametrized motion planning algorithms have high degree of flexibility and universality, they can work under a variety of external conditions, which are viewed as parameters and form part of the input of the algorithm. In this paper we…

Algebraic Topology · Mathematics 2022-05-13 Michael Farber , Shmuel Weinberger

The lower and the upper irredundance numbers of a graph $G$, denoted $ir(G)$ and $IR(G)$ respectively, are conceptually linked to domination and independence numbers and have numerous relations to other graph parameters. It is a…

Given an undirected graph with edge weights and a subset $R$ of its edges, the Rural Postman Problem (RPP) is to find a closed walk of minimum total weight containing all edges of $R$. We prove that RPP is WK[1]-complete parameterized by…

Data Structures and Algorithms · Computer Science 2021-01-14 René van Bevern , Till Fluschnik , Oxana Yu. Tsidulko

The embedding problem is to decide, given an ordered pair of structures, whether or not there is an injective homomorphism from the first structure to the second. We study this problem using an established perspective in parameterized…

Computational Complexity · Computer Science 2017-01-09 Hubie Chen , Moritz Müller

In this paper, we investigate the parameterized complexity of model checking for Dependence Logic which is a well studied logic in the area of Team Semantics. We start with a list of nine immediate parameterizations for this problem,…

Logic in Computer Science · Computer Science 2021-09-21 Juha Kontinen , Arne Meier , Yasir Mahmood

We show that approximating the trace norm contraction coefficient of a quantum channel within a constant factor is NP-hard. Equivalently, this shows that determining the optimal success probability for encoding a bit in a quantum system…

Quantum Physics · Physics 2025-09-23 Idris Delsol , Omar Fawzi , Jan Kochanowski , Akshay Ramachandran

We construct a new order 1 invariant for knot diagrams. We use it to determine the minimal number of Reidemeister moves needed to pass between certain pairs of knot diagrams.

Geometric Topology · Mathematics 2007-08-21 Joel Hass , Tahl Nowik

A strength of parameterized algorithmics is that each problem can be parameterized by an essentially inexhaustible set of parameters. Usually, the choice of the considered parameter is informed by the theoretical relations between…

Computational Complexity · Computer Science 2026-05-05 Christian Komusiewicz , Nils Morawietz , Frank Sommer , Luca Pascal Staus

We study the following general stabbing problem from a parameterized complexity point of view: Given a set $\mathcal S$ of $n$ translates of an object in $\Rd$, find a set of $k$ lines with the property that every object in $\mathcal S$ is…

Computational Geometry · Computer Science 2015-02-18 Panos Giannopoulos , Christian Knauer , Gunter Rote , Daniel Werner

A \emph{2-interval} is the union of two disjoint intervals on the real line. Two 2-intervals $D_1$ and $D_2$ are \emph{disjoint} if their intersection is empty (i.e., no interval of $D_1$ intersects any interval of $D_2$). There can be…

Computational Geometry · Computer Science 2020-02-13 Prosenjit Bose , Saeed Mehrabi , Debajyoti Mondal

Every classical or virtual knot is equivalent to the unknot via a sequence of extended Reidemeister moves and the so-called forbidden moves. The minimum number of forbidden moves necessary to unknot a given knot is an invariant we call the…

Geometric Topology · Mathematics 2018-08-14 Alissa Crans , Sandy Ganzell , Blake Mellor

Parameterised subgraph counting problems are the most thoroughly studied topic in the theory of parameterised counting, and there has been significant recent progress in this area. Many of the existing tractability results for parameterised…

Computational Complexity · Computer Science 2015-06-01 Kitty Meeks

We study the NP-hard Shortest Path Most Vital Edges problem arising in the context of analyzing network robustness. For an undirected graph with positive integer edge lengths and two designated vertices $s$ and $t$, the goal is to delete as…

Computational Complexity · Computer Science 2018-04-25 Cristina Bazgan , Till Fluschnik , André Nichterlein , Rolf Niedermeier , Maximilian Stahlberg

In this paper we study the hardness of the syndrome decoding problem over finite rings endowed with the Lee metric. We first prove that the decisional version of the problem is NP-complete, by a reduction from the $3$-dimensional matching…

Information Theory · Computer Science 2022-04-04 Violetta Weger , Karan Khathuria , Anna-Lena Horlemann , Massimo Battaglioni , Paolo Santini , Edoardo Persichetti

The task of the broadcast problem is, given a graph G and a source vertex s, to compute the minimum number of rounds required to disseminate a piece of information from s to all vertices in the graph. It is assumed that, at each round, an…

Data Structures and Algorithms · Computer Science 2023-06-05 Fedor V. Fomin , Pierre Fraigniaud , Petr A. Golovach

We consider the classic problem of Network Reliability. A network is given together with a source vertex, one or more target vertices, and probabilities assigned to each of the edges. Each edge appears in the network with its associated…

Combinatorics · Mathematics 2019-03-20 Amir Kafshdar Goharshady , Fatemeh Mohammadi

We investigate the computational complexity of some problems in three-dimensional topology and geometry. We show that the problem of determining a bound on the genus of a knot in a 3-manifold, is NP-complete. Using similar ideas, we show…

Geometric Topology · Mathematics 2007-05-23 Ian Agol , Joel Hass , William P. Thurston

We consider the problem of reducing the (semi)total domination number of graph by one by contracting edges. It is known that this can always be done with at most three edge contractions and that deciding whether one edge contraction…

Discrete Mathematics · Computer Science 2022-05-26 Esther Galby

Asking which sets are fixed-parameter tractable for a given parameterization constitutes much of the current research in parameterized complexity theory. This approach faces some of the core difficulties in complexity theory. By focussing…

Logic in Computer Science · Computer Science 2018-01-17 Jouke Witteveen , Leen Torenvliet

Vertex deletion problems for graphs are studied intensely in classical and parameterized complexity theory. They ask whether we can delete at most k vertices from an input graph such that the resulting graph has a certain property.…

Logic in Computer Science · Computer Science 2024-06-27 Max Bannach , Florian Chudigiewitsch , Till Tantau