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Related papers: Upper bounds on the graph minor theorem

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We prove a minimum degree version of the Kruskal--Katona theorem: given $d\ge 1/4$ and a triple system $F$ on $n$ vertices with minimum degree at least $d\binom n2$, we obtain asymptotically tight lower bounds for the size of its shadow.…

Combinatorics · Mathematics 2022-07-19 Zoltán Füredi , Yi Zhao

An inequality proved firstly by Remak and then generalized by Friedman shows that there are only finitely many number fields with a fixed signature and whose regulator is less than a prescribed bound. Using this inequality, Astudillo, Diaz…

Number Theory · Mathematics 2021-06-03 Francesco Battistoni

A major step in the graph minors theory of Robertson and Seymour is the transition from the Grid Theorem which, in some sense uniquely, describes areas of large treewidth within a graph, to a notion of local flatness of these areas in form…

Combinatorics · Mathematics 2021-10-15 Archontia C. Giannopoulou , Sebastian Wiederrecht

Motivated by the study of greedy algorithms for graph coloring, Bernshteyn and Lee introduced a generalization of graph degeneracy, which is called weak degeneracy. In this paper, we show the lower bound of the weak degeneracy for…

Combinatorics · Mathematics 2023-10-02 Yuxuan Yang

We provide lower and upper bounds on the minimum size of a maximum stable set over graphs of flag spheres, as a function of the dimension of the sphere and the number of vertices. Further, we use stable sets to obtain an improved Lower…

Combinatorics · Mathematics 2022-04-05 Maria Chudnovsky , Eran Nevo

We prove an upper bound on sums of squares of minors of {+1, -1} matrices. The bound is sharp for Hadamard matrices, a result due to de Launey and Levin (2009), but our proof is simpler. We give several corollaries relevant to minors of…

Combinatorics · Mathematics 2013-09-10 Richard P. Brent , Judy-anne H. Osborn

The recent paper "Linear Connectivity Forces Large Complete Bipartite Minors" by Boehme et al. relies on a structure theorem for graphs with no H-minor. The sketch provided of how to deduce this theorem from the work of Robertson and…

Combinatorics · Mathematics 2009-06-16 Jan-Oliver Fröhlich , Theodor Müller

The best degree-based upper bound for the spectral radius is due to Liu and Weng. This paper begins by demonstrating that a (forgotten) upper bound for the spectral radius dating from 1983 is equivalent to their much more recent bound. This…

Combinatorics · Mathematics 2014-10-07 Clive Elphick , Chia-an Liu

We determine upper and lower bounds on the zero forcing number of 2-connected outerplanar graphs in terms of the structure of the weak dual. We show that the upper bound is always at most half the number of vertices of the graph. This work…

Combinatorics · Mathematics 2023-08-23 Nolan Ison , Mark Kempton , Franklin Kenter

Let $G$ be a graph, and let $\lambda(G)$ denote the smallest eigenvalue of $G$. First, we provide an upper bound for $\lambda(G)$ based on induced bipartite subgraphs of $G$. Consequently, we extract two other upper bounds, one relying on…

Combinatorics · Mathematics 2024-04-16 Aryan Esmailpour , Sara Saeedi Madani , Dariush Kiani

Mader first proved that high average degree forces a given graph as a minor. Often motivated by Hadwiger's Conjecture, much research has focused on the average degree required to force a complete graph as a minor. Subsequently, various…

Combinatorics · Mathematics 2017-07-18 Daniel J. Harvey , David R. Wood

The topic is the average order of a connected induced subgraph of a graph. This generalizes, to graphs in general, the average order of a subtree of a tree. In 1984, Jamison proved that the average order, over all trees of order $n$, is…

Combinatorics · Mathematics 2021-03-30 Andrew Vince

We prove an upper bound of $n+9$ for the strong separation number of the complete graph $K_n$, and an upper bound of $n+1$ for its weak separation number. This improves on the previous best known bound of $(1+o(1))n$ for both cases.

Combinatorics · Mathematics 2026-03-25 George Kontogeorgiou , Maya Stein

In recent years there has been increased interest in extremal problems for "counting" parameters of graphs. For example, the Kahn-Zhao theorem gives an upper bound on the number of independent sets in a $d$-regular graph. In the same…

Combinatorics · Mathematics 2013-10-08 L. Keough , A. J. Radcliffe

A one-line proof of a minimax theorem due to Steinerberger is given.

Combinatorics · Mathematics 2024-05-24 Yi C. Huang

The crossing number of a graph $G$ denotes the minimum number of crossings in any planar drawing of $G$. In this short note, we confirm a long-standing conjecture posed by Pach, Spencer, and T\'oth over 25 years ago, establishing an optimal…

Combinatorics · Mathematics 2025-02-05 Kaizhe Chen , Jie Ma

In this note we give a new upper bound for the Laplacian eigenvalues of an unweighted graph. Let $G$ be a simple graph on $n$ vertices. Let $d_{m}(G)$ and $\lambda_{m+1}(G)$ be the $m$-th smallest degree of $G$ and the $m+1$-th smallest…

Combinatorics · Mathematics 2011-06-07 Miriam Farber , Ido Kaminer

We give a sharp lower bound on the lower $k$-limited packing number of a general graph. Moreover, we establish a Nordhaus-Gaddum type bound on $2$-limited packing number of a graph. Also, we investigate the concepts of packing number…

Combinatorics · Mathematics 2019-08-27 Babak Samadi

The problem of determining the maximum number of maximal independent sets in certain graph classes dates back to a paper of Miller and Muller and a question of Erd\H{o}s and Moser from the 1960s. The minimum was always considered to be less…

Combinatorics · Mathematics 2024-09-17 Stijn Cambie , Stephan Wagner

We give upper bounds on weighted perfect matchings in pfaffian graphs. These upper bounds are better than Bregman's upper bounds on the number of perfect matchings. We show that some of our upper bounds are sharp for 3 and 4-regular…

Combinatorics · Mathematics 2013-01-01 Afshin Behmaram , Shmuel Friedland
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