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Related papers: On an induced version of Menger's theorem

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For an acyclic directed graph with multiple sources and multiple sinks, we prove that one can choose the Merger's paths between the sources and the sinks such that the number of mergings between these paths is upper bounded by a constant…

Information Theory · Computer Science 2011-04-29 Guangyue Han

A graph is path-pairable if for any pairing of its vertices there exist edge-disjoint paths joining the vertices in each pair. We investigate the behaviour of the maximum degree in path-pairable planar graphs. We show that any $n$-vertex…

Combinatorics · Mathematics 2017-05-18 António Girão , Gábor Mészáros , Kamil Popielarz , Richard Snyder

In this paper we study variations of an old result by M\"{u}ller, Reiterman, and the last author stating that a countable graph has a subgraph with infinite degrees if and only if in any labeling of the vertices (or edges) of this graph by…

Combinatorics · Mathematics 2019-05-10 Andrii Arman , Bradley Elliott , Vojtěch Rödl

In this note we asymptotically determine the maximum number of hyperedges possible in an $r$-uniform, connected $n$-vertex hypergraph without a Berge path of length $k$, as $n$ and $k$ tend to infinity. We show that, unlike in the graph…

Combinatorics · Mathematics 2017-10-24 Ervin Győri , Abhishek Methuku , Nika Salia , Casey Tompkins , Máté Vizer

Consider an acyclic directed network $G$ with sources $S_1, S_2,..., S_l$ and distinct sinks $R_1, R_2,..., R_l$. For $i=1, 2,..., l$, let $c_i$ denote the min-cut between $S_i$ and $R_i$. Then, by Menger's theorem, there exists a group of…

Information Theory · Computer Science 2013-01-10 Li Xu , Weiping Shang , Guangyue Han

In this paper, we prove a collection of results on graphical indices. We determine the extremal graphs attaining the maximal generalized Wiener index (e.g. the hyper-Wiener index) among all graphs with given matching number or independence…

Combinatorics · Mathematics 2023-06-22 Stijn Cambie

We extend the edge version of the classical Menger's Theorem for undirected graphs to $n$-dimensional simplicial complexes with chains over the field $\mathbb{F}_2$. The classical Menger's Theorem states that two different vertices in an…

Geometric Topology · Mathematics 2021-11-19 Avraham Goldstein , Yonah Cherniavsky

A paradigm that was successfully applied in the study of both pure and algorithmic problems in graph theory can be colloquially summarized as stating that "any graph is close to being the disjoint union of expanders". Our goal in this paper…

Combinatorics · Mathematics 2015-02-03 Guy Moshkovitz , Asaf Shapira

Given a finite set of points in $\mathbb{R}^d$, Tverberg's theorem guarantees the existence of partitions of this set into parts whose convex hulls intersect. We introduce a graph structured on the family of Tverberg partitions of a given…

Combinatorics · Mathematics 2023-10-13 Deborah Oliveros , Érika Roldán , Pablo Soberón , Antonio J. Torres

Let G be a graph with minimum degree $\delta$. It is well-known that maximal adjacency orderings (MAOs) compute a vertex set S such that every pair of S is connected by at least $\delta$ internally vertex-disjoint paths in G. We present an…

Discrete Mathematics · Computer Science 2016-09-22 Johanna E. Preißer , Jens M. Schmidt

We expand upon the notion of bottlenecking introduced in our earlier work, characterizing a spectrum of graphs and showing that this naturally extends to a concept of coarse bottlenecking. We show how the notion of bottlenecking provides a…

Metric Geometry · Mathematics 2024-10-23 Michael Bruner , Atish Mitra , Heidi Steiger

We present new min-max relations in digraphs between the number of paths satisfying certain conditions and the order of the corresponding cuts. We define these objects in order to capture, in the context of solving the half-integral linkage…

Combinatorics · Mathematics 2023-06-29 Victor Campos , Jonas Costa , Raul Lopes , Ignasi Sau

The topological Tverberg theorem claims that for any continuous map of the (q-1)(d+1)-simplex to R^d there are q disjoint faces such that their images have a non-empty intersection. This has been proved for affine maps, and if $q$ is a…

Combinatorics · Mathematics 2008-02-25 Stephan Hell

For an $n$-vertex graph $G$, let $z(G;k)$ denote the number of zero forcing sets of size $k$. A conjecture of Boyer et al. asserts that the path $P_n$ maximizes these numbers coefficientwise among all $n$-vertex graphs; equivalently, the…

Discrete Mathematics · Computer Science 2026-05-12 Samuel German

This work concerns results on conditions guaranteeing that certain banded $M$-matrices have banded inverses. As a first goal, a graph theoretic characterization for an off-diagonal entry of the inverse of an $M$-matrix to be positive, is…

General Mathematics · Mathematics 2024-12-30 S. Pratihar , K. C. Sivakumar

We consider the class of directed graphs with $N\geq 1$ edges and without loops shorter than $k\geq1$. Using the concept of a labelled graph, we determine graphs from this class that maximize the number of all paths of length $k$. Then we…

Combinatorics · Mathematics 2026-03-24 Piotr M. Hajac , Oskar M. Stachowiak

We study a generalization of the well-known disjoint paths problem which we call the metric Menger problem, denoted MM(r,k), where one is given two subsets of a graph and must decide whether they can be connected by $k$ paths of pairwise…

Combinatorics · Mathematics 2024-03-12 Júlia Baligács , Joseph MacManus

For a graph $G$, let $\nu_s(G)$ be the induced matching number of $G$. We prove that $\nu_s(G) \geq \frac{n(G)}{(\lceil\frac{\Delta}{2}\rceil+1) (\lfloor\frac{\Delta}{2}\rfloor+1)}$ for every graph of sufficiently large maximum degree…

Combinatorics · Mathematics 2014-06-11 Felix Joos

The undirected underlying graph of a 2-quasi best match graph (2-qBMG) is proven not to contain any induced graph isomorphic to $P_6$ or $C_6$. This new feature allows for the investigation of 2-BMGs further by exploiting the numerous known…

Combinatorics · Mathematics 2024-08-20 Annachiara Korchmaros

The classical Menger's theorem states that in any undirected (or directed) graph $G$, given a pair of vertices $s$ and $t$, the maximum number of vertex (edge) disjoint paths is equal to the minimum number of vertices (edges) needed to…

Data Structures and Algorithms · Computer Science 2015-09-21 Ashutosh Rai , M. S. Ramanujan , Saket Saurabh