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A geometric $t$-spanner $\mathcal{G}$ on a set $S$ of $n$ point sites in a metric space $P$ is a subgraph of the complete graph on $S$ such that for every pair of sites $p,q$ the distance in $\mathcal{G}$ is a most $t$ times the distance…

Computational Geometry · Computer Science 2024-09-20 Sarita de Berg , Tim Ophelders , Irene Parada , Frank Staals , Jules Wulms

An algebraic telic problem is a decision problem in $\textsf{NP}_\mathbb{R}$ formalizing finite-time reachability questions for one-dimensional dynamical systems. We prove that the existence of "natural" mapping reductions between algebraic…

Computational Complexity · Computer Science 2026-01-16 Samuel Everett

A matching cut is a matching that is also an edge cut. In the problem Minimum Matching Cut, we ask for a matching cut with the minimum number of edges in the matching. We investigate the differences in complexity between Minimum Matching…

Combinatorics · Mathematics 2026-02-20 Felicia Lucke , Joseph Marchand , Jannik Olbrich

Link/knot invariants are series with integer coefficients, and it is a long-standing problem to get them positive and possessing cohomological interpretation. Constructing positive "superpolynomials" is not straightforward, especially for…

High Energy Physics - Theory · Physics 2020-10-01 A. Mironov , A. Morozov

Every finite graph admits a \emph{simple (topological) drawing}, that is, a drawing where every pair of edges intersects in at most one point. However, in combination with other restrictions simple drawings do not universally exist. For…

Computational Geometry · Computer Science 2020-08-26 Michael Hoffmann , Chih-Hung Liu , Meghana M. Reddy , Csaba D. Tóth

The growing amount of applications that generate vast amount of data in short time scales render the problem of partial monitoring, coupled with prediction, a rather fundamental one. We study the aforementioned canonical problem under the…

Data Structures and Algorithms · Computer Science 2016-08-02 Michalis Kallitsis , Stilian Stoev , George Michailidis

We study the recognition complexity of subgraphs of k-connected planar cubic graphs for k = 1, 2, 3. We present polynomial-time algorithms to recognize subgraphs of 1- and 2-connected planar cubic graphs, both in the variable and fixed…

Discrete Mathematics · Computer Science 2024-10-15 Miriam Goetze , Paul Jungeblut , Torsten Ueckerdt

Finding a smallest subgraph that is k-edge-connected, or augmenting a k-edge-connected graph with a smallest subset of given candidate edges to become (k+1)-edge-connected, are among the most fundamental Network Design problems. They are…

Data Structures and Algorithms · Computer Science 2025-12-25 Meike Neuwohner , Vera Traub , Rico Zenklusen

In a wide range of complex networks, the links between the nodes are temporal and may sporadically appear and disappear. This temporality is fundamental to analyze the formation of paths within such networks. Moreover, the presence of the…

Physics and Society · Physics 2017-09-20 Shahriar Etemadi Tajbakhsh , Justin P. Coon , David E. Simmons

Kuperberg [Algebr. Geom. Topol. 3 (2003) 587-591] has shown that a virtual knot corresponds (up to generalized Reidemeister moves) to a unique embedding in a thichened surface of minimal genus. If a virtual knot diagram is equivalent to a…

Geometric Topology · Mathematics 2014-10-01 H. A. Dye , Louis H. Kauffman

We develop a topological lens on relational schema design by encoding functional dependencies (FDs) as simplices of an abstract simplicial complex. This dependency complex exposes multi-attribute interactions and enables homological…

Databases · Computer Science 2026-02-26 Bilge Senturk , Faruk Alpay

To learn (statistical) dependencies among random variables requires exponentially large sample size in the number of observed random variables if any arbitrary joint probability distribution can occur. We consider the case that sparse data…

Machine Learning · Computer Science 2007-05-23 Dominik Janzing , Daniel Herrmann

We study a problem of reconstruction of connected graphs where the input gives all subsets of size k that induce a connected subgraph. Originally introduced by Bastide et al. (WG 2023) for triples ($k=3$), this problem received…

Combinatorics · Mathematics 2024-07-11 Kacper Kluk , Hoang La , Marta Piecyk

Hybrid logic with binders is an expressive specification language. Its satisfiability problem is undecidable in general. If frames are restricted to N or general linear orders, then satisfiability is known to be decidable, but of…

Computational Complexity · Computer Science 2012-06-13 Stefan Göller , Arne Meier , Martin Mundhenk , Thomas Schneider , Michael Thomas , Felix Weiss

Complex networks can be understood as graphs whose connectivity deviates from those of regular or near-regular graphs, which are understood as being `simple'. While a great deal of the attention so far dedicated to complex networks has been…

Data Analysis, Statistics and Probability · Physics 2008-08-29 Luciano da Fontoura Costa , Francisco A. Rodrigues

We introduce a new numerical knot invariant, termed the \textit{segment number}, which is derived from partitioned knot diagrams subject to specific over/under-crossing constraints. We prove that a knot is non-trivial if and only if its…

Geometric Topology · Mathematics 2026-02-19 Makoto Ozawa

We prove that every digraph of circumference $l$ has DAG-width at most $l$ and this is best possible. As a consequence of our result we deduce that the $k$-linkage problem is polynomially solvable for every fixed $k$ in the class of…

Discrete Mathematics · Computer Science 2015-02-12 Jørgen Bang-Jensen , Tilde My Larsen

We continue to study Cayley configuration spaces of 1-dof linkages in 2D begun in Part I of this paper, i.e. the set of attainable lengths for a non-edge. In Part II, we focus on the algebraic complexity of describing endpoints of the…

Computational Geometry · Computer Science 2015-03-19 Meera Sitharam , Menghan Wang , Heping Gao

A linking system of difference sets is a collection of mutually related group difference sets, whose advantageous properties have been used to extend classical constructions of systems of linked symmetric designs. The central problems are…

Combinatorics · Mathematics 2018-04-23 Jonathan Jedwab , Shuxing Li , Samuel Simon

The regular number of a graph G denoted by reg(G) is the minimum number of subsets into which the edge set of G can be partitioned so that the subgraph induced by each subset is regular. In this work we answer to the problem posed as an…

Combinatorics · Mathematics 2014-06-09 Ali Dehghan , Mohammad-Reza Sadeghi , Arash Ahadi