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Let $G$ be an undirected graph. We say that $G$ contains a ladder of length $k$ if the $2 \times (k+1)$ grid graph is an induced subgraph of $G$ that is only connected to the rest of $G$ via its four cornerpoints. We prove that if all the…

Combinatorics · Mathematics 2024-01-31 Steven Chaplick , Steven Kelk , Ruben Meuwese , Matus Mihalak , Georgios Stamoulis

We establish a new fundamental relationship between total curvature of knots and crossing number. If K is a smooth knot in 3-space, R the cross-section radius of a uniform tube neighborhood of K, L the arclength of K, and k the total…

Geometric Topology · Mathematics 2007-05-23 Gregory Buck , Jonathan Simon

Inspired by the seminal works of Khuller et al. (STOC 1994) and Chan (SoCG 2003) we study the bottleneck version of the Euclidean bounded-degree spanning tree problem. A bottleneck spanning tree is a spanning tree whose largest edge-length…

Computational Geometry · Computer Science 2019-11-21 Ahmad Biniaz

In this article we study the braid indices of 2-bridge knots with a fixed crossing number $c$. We show that the average braid index of the set of $2$-bridge knots of crossing number $c$ is asymptotically linear, approaching…

Geometric Topology · Mathematics 2024-01-17 Tobias Clark , Jeremy Frank , Adam M. Lowrance

The k-core of a graph G is the maximal subgraph of G having minimum degree at least k. In 1996, Pittel, Spencer and Wormald found the threshold $\lambda_c$ for the emergence of a non-trivial k-core in the random graph $G(n,\lambda/n)$, and…

Combinatorics · Mathematics 2009-05-08 Oliver Riordan

The Kirchhoff index of a connected graph is the sum of resistance distances between all unordered pairs of vertices in the graph. Its considerable applications are found in a variety of fields. In this paper, we determine the maximum value…

Combinatorics · Mathematics 2015-11-06 Dong Li , Xiang-Feng Pan , Jia-Bao Liu , Hui-Qing Liu

In this paper, we introduce a bisected vertex leveling of a plane graph. Using this planar embedding, we present elementary proofs of the well-known upper bounds in terms of the minimal crossing number on braid index $b(L)$ and arc index…

Geometric Topology · Mathematics 2018-06-27 Sungjong No , Seungsang Oh , Hyungkee Yoo

A $k$-ranking of a graph $G$ is a labeling of its vertices from $\{1,\ldots,k\}$ such that any nontrivial path whose endpoints have the same label contains a larger label. The least $k$ for which $G$ has a $k$-ranking is the ranking number…

Combinatorics · Mathematics 2014-01-14 Daniel C. McDonald

The determination of the braid index of an oriented link is generally a hard problem. In the case of alternating links, some significant progresses have been made in recent years which made explicit and precise braid index computations…

Geometric Topology · Mathematics 2024-03-22 Yuanan Diao , Claus Ernst , Gabor Hetyei

To an oriented link in a solid torus we associate a trace graph in a thickened torus in such a way that links are isotopic if and only if their trace graphs can be related by moves of finitely many standard types. The key ingredient is a…

Geometric Topology · Mathematics 2008-10-23 T. Fiedler , V. Kurlin

The {\em atom-bond connectivity (ABC) index} is a degree-based graph topological index that found chemical applications. The problem of complete characterization of trees with minimal $ABC$ index is still an open problem.…

Discrete Mathematics · Computer Science 2015-01-26 Darko Dimitrov

A linked bar chart is the augmentation of a traditional bar chart where each bar is partitioned into blocks and pairs of blocks are linked using orthogonal lines that pass over intermediate bars. The order of the blocks readily influences…

Computational Geometry · Computer Science 2025-11-24 Steven van den Broek , Marc van Kreveld , Wouter Meulemans , Arjen Simons

Every knot can be embedded in the union of finitely many half planes with a common boundary line in such a way that the portion of the knot in each half plane is a properly embedded arc. The minimal number of such half planes is called the…

Geometric Topology · Mathematics 2010-10-15 Gyo Taek Jin , Wang Keun Park

In this paper we are interested in BB knots, namely knots and links where the bridge index equals the braid index. Supported by observations from experiments, it is conjectured that BB knots possess a special geometric/physical property…

Geometric Topology · Mathematics 2021-08-27 Yuanan Diao , Claus Ernst , Philipp Reiter

We investigate relations between different width parameters of graphs, in particular balanced separator number, treewidth, and cycle rank. Our main result states that a graph with balanced separator number k has treewidth at least k but…

Discrete Mathematics · Computer Science 2015-03-17 Hermann Gruber

Let $\phi : S^1\times D^2\to S^1$ be the natural projection. An oriented knot $K\hookrightarrow V = S^1\times D^2$ is called an almost closed braid if the restriction of $\phi$ to K has exactly two (non-degenerate) critical points (and K is…

Geometric Topology · Mathematics 2007-05-23 Thomas Fiedler

We study limits of the largest connected components (viewed as metric spaces) obtained by critical percolation on uniformly chosen graphs and configuration models with heavy-tailed degrees. For rank-one inhomogeneous random graphs, such…

Probability · Mathematics 2020-05-11 Shankar Bhamidi , Souvik Dhara , Remco van der Hofstad , Sanchayan Sen

We define braid presentation of edge-oriented spatial graphs as a natural generalization of braid presentation of oriented links. We show that every spatial graph has a braid presentation. For an oriented link it is known that the braid…

Geometric Topology · Mathematics 2009-01-13 Ken Kanno , Kouki Taniyama

A $k$-tree is a spanning tree in which every vertex has degree at most $k$. In this paper, we provide a sufficient condition for the existence of a $k$-tree in a connected graph with fixed order in terms of the adjacency spectral radius and…

Combinatorics · Mathematics 2023-04-24 Dandan Fan , Sergey Goryainov , Xueyi Huang , Huiqiu Lin

We prove that fibred knots cannot be untied with $\bar{t}_{2k}$-moves, for all $k \geq 2$. More generally, we give an upper bound on the number of two strand twist operations that allow to untie a knot with non-trivial HOMFLY polynomial, in…

Geometric Topology · Mathematics 2022-09-15 Lambert A'Campo , Sebastian Baader , Livio Ferretti , Levi Ryffel