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Building on prior work that established Matrix Quasi-tree Theorems for special embedded graphs, in this paper, we develop a comprehensive theory applicable to all embedded graphs. We introduce symbolic skew-adjacency matrices and reduction…

Combinatorics · Mathematics 2025-12-02 Qingying Deng , Xian'an Jin , Qi Yan , Yexiang Yan

In this paper we show how to find nearly optimal embeddings of large trees in several natural classes of graphs. The size of the tree T can be as large as a constant fraction of the size of the graph G, and the maximum degree of T can be…

Combinatorics · Mathematics 2007-07-17 Benny Sudakov , Jan Vondrak

Weak similarities form a special class of mappings between semimetric spaces. Two semimetric spaces $X$ and $Y$ are weakly similar if there exists a weak similarity $\Phi\colon X\to Y$. We find a structural characteristic of finite…

General Topology · Mathematics 2024-12-31 Evgeniy Petrov

There are several common ways to encode a tree as a matrix, such as the adjacency matrix, the Laplacian matrix (that is, the infinitesimal generator of the natural random walk), and the matrix of pairwise distances between leaves. Such…

Populations and Evolution · Quantitative Biology 2007-05-23 Frederick A. Matsen , Steven N. Evans

The Calkin-Wilf tree is an infinite binary tree whose vertices are the positive rational numbers. Each number occurs in the tree exactly once and in the form $a/b$, where are $a$ and $b$ are relatively prime positive integers. In this…

Number Theory · Mathematics 2020-04-17 Melvyn B. Nathanson

We construct quasi-isometry invariants of a one-ended finitely presented group by considering the tree of cylinders of a two-ended JSJ decomposition of the group. When the group satisfies additional quasi-isometric rigidity hypotheses we…

Group Theory · Mathematics 2016-01-28 Christopher H. Cashen

Fitting distances to tree metrics and ultrametrics are two widely used methods in hierarchical clustering, primarily explored within the context of numerical taxonomy. Given a positive distance function…

Data Structures and Algorithms · Computer Science 2025-04-25 Amir Carmel , Debarati Das , Evangelos Kipouridis , Evangelos Pipis

We show that every connected graph can be approximated by a normal tree, up to some arbitrarily small error phrased in terms of neighbourhoods around its ends. The existence of such approximate normal trees has consequences of both…

Combinatorics · Mathematics 2021-02-05 Jan Kurkofka , Ruben Melcher , Max Pitz

We construct near optimal linear decision trees for a variety of decision problems in combinatorics and discrete geometry. For example, for any constant $k$, we construct linear decision trees that solve the $k$-SUM problem on $n$ elements…

Computational Geometry · Computer Science 2017-05-05 Daniel M. Kane , Shachar Lovett , Shay Moran

Using non-trivial mathematical properties of a class of nonlinear evolution equations, we obtain the universal terms in the asymptotic expansion in rapidity of the saturation scale and of the unintegrated gluon density from the…

High Energy Physics - Phenomenology · Physics 2008-11-26 S. Munier , R. Peschanski

We prove that given a discrete space with $n$ points which is either embedded in a system of $k$ trees, or the Cartesian product of $k$ trees, we can compute all eccentricities in ${\cal O}(2^{{\cal O}(k\log{k})}(N+n)^{1+o(1)})$ time, where…

Data Structures and Algorithms · Computer Science 2020-10-30 Guillaume Ducoffe

We prove a "uniform" version of the finite density Halpern-L\"{a}uchli Theorem. Specifically, we say that a tree $T$ is homogeneous if it is uniquely rooted and there is an integer $b\geq 2$, called the branching number of $T$, such that…

Combinatorics · Mathematics 2013-03-20 Pandelis Dodos , Vassilis Kanellopoulos , Konstantinos Tyros

Let $L$ be a fixed branch -- that is, an irreducible germ of curve -- on a normal surface singularity $X$. If $A,B$ are two other branches, define $u_L(A,B) := \dfrac{(L \cdot A) \: (L \cdot B)}{A \cdot B}$, where $A \cdot B$ denotes the…

Algebraic Geometry · Mathematics 2019-10-07 Evelia García Barroso , Pedro González Pérez , Patrick Popescu-Pampu , Matteo Ruggiero

In this work we introduce the notion of almost-symmetry for generalized numerical semigroups. In addition to the main properties occurring in this new class, we present several characterizations for its elements. In particular we show that…

Combinatorics · Mathematics 2020-12-29 Carmelo Cisto , Wanderson Tenório

While research on the geometry of planar graphs has been active in the past decades, many properties of planar metrics remain mysterious. This paper studies a fundamental aspect of the planar graph geometry: covering planar metrics by a…

Data Structures and Algorithms · Computer Science 2023-11-07 Hsien-Chih Chang , Jonathan Conroy , Hung Le , Lazar Milenkovic , Shay Solomon , Cuong Than

In this paper we examine the relationship between hyperconvex hulls and metric trees. After providing a linking construction for hyperconvex spaces, we show that the four-point property is inherited by the hyperconvex hull, which leads to…

Metric Geometry · Mathematics 2007-05-23 A. G. Aksoy , B. Maurizi

One-dimensional quasiperiodic systems, such as the Harper model and the Fibonacci quasicrystal, have long been the focus of extensive theoretical and experimental research. Recently, the Harper model was found to be topologically…

Strongly Correlated Electrons · Physics 2015-03-20 Yaacov E. Kraus , Oded Zilberberg

A transversal in a rooted tree is any set of nodes that meets every path from the root to a leaf. We let c(T,k) denote the number of transversals of size k in a rooted tree T. We define a partial order on the set of all rooted trees with n…

Combinatorics · Mathematics 2013-08-20 Victor Campos , Vasek Chvatal , Luc Devroye , Perouz Taslakian

A Riemannian or pseudo-Riemannian (or conformal) structure is conformally Einstein if and only if there is a suitably generic parallel section of a certain vector bundle -- the so-called standard conformal tractor bundle. We show that this…

Differential Geometry · Mathematics 2007-05-23 A. R. Gover

In this paper we provide two new constructions that are useful for the theory of projection complexes developed by Bestvina, Bromberg, Fujiwara and Sisto. We prove that there exists a subtree of the projection complex which is…

Group Theory · Mathematics 2024-12-18 Patrick S. Nairne