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Phylogenetic trees canonically arise as embeddings of phylogenetic networks. We recently showed that the problem of deciding if two phylogenetic networks embed the same sets of phylogenetic trees is computationally hard, \blue{in…

Combinatorics · Mathematics 2021-04-13 Janosch Doecker , Simone Linz , Charles Semple

The paper proposes a new variant of a decision tree, called an Extreme Learning Tree. It consists of an extremely random tree with non-linear data transformation, and a linear observer that provides predictions based on the leaf index where…

Machine Learning · Computer Science 2019-12-20 Anton Akusok , Emil Eirola , Kaj-Mikael Björk , Amaury Lendasse

A graph $G$ is asymmetrizable if it has a set of vertices whose setwise stablizer only consists of the identity automorphism. The motion $m$ of a graph is the minimum number of vertices moved by any non-identity automorphism. It is known…

Combinatorics · Mathematics 2023-01-26 Wilfried Imrich , Rafał Kalinowski , Florian Lehner , Monika Pilśniak , Marcin Stawiski

Some posets of binary leaf-labeled trees are shown to be supersolvable lattices and explicit EL-labelings are given. Their characteristic polynomials are computed, recovering their known factorization in a different way.

Combinatorics · Mathematics 2007-05-23 Riccardo Biagioli , Frederic Chapoton

Phylogenetic (i.e. leaf-labeled) trees play a fundamental role in evolutionary research. A typical problem is to reconstruct such trees from data like DNA alignments (whose columns are often referred to as characters), and a simple…

Populations and Evolution · Quantitative Biology 2022-09-08 Mareike Fischer

We divide the class of infinite computable trees into three types. For the first and second types, $0'$ computes a nontrivial self-embedding while for the third type $0''$ computes a nontrivial self-embedding. These results are optimal and…

In this paper, we address the problem of packing large trees in $G_{n,p}$. In particular, we prove the following result. Suppose that $T_1, \dotsc, T_N$ are $n$-vertex trees, each of which has maximum degree at most $(np)^{1/6} / (\log…

Combinatorics · Mathematics 2018-10-03 Asaf Ferber , Wojciech Samotij

Traditional Quartet Puzzling algorithms use maximum likelihood methods to reconstruct quartet trees, and a puzzling algorithm to combine these quartets into a tree for the full collection of $n$ taxa. We propose a variation of Quartet…

Populations and Evolution · Quantitative Biology 2011-10-31 Joe Rusinko , Brian Hipp

In this paper, we investigate the structures of an extremal tree which has the minimal number of subtrees in the set of all trees with the given degree sequence of a tree. In particular, the extremal trees must be caterpillar and but in…

Combinatorics · Mathematics 2012-09-04 Xiu-Mei Zhang , Xiao-Dong Zhang

The paper gives an example of a tree language G that is recognised by an unambiguous parity automaton and is analytic-complete as a set in Cantor space. This already shows that the unambiguous languages are topologically more complex than…

Formal Languages and Automata Theory · Computer Science 2012-10-10 Szczepan Hummel

This article focuses on properties and structures of trees with maximum mean subtree order in a given family; such trees are called optimal in the family. Our main goal is to describe the structure of optimal trees in $\mathcal{T}_n$ and…

Combinatorics · Mathematics 2018-11-16 Lucas Mol , Ortrud R. Oellermann

The MULTICUT IN TREES problem consists in deciding, given a tree, a set of requests (i.e. paths in the tree) and an integer k, whether there exists a set of k edges cutting all the requests. This problem was shown to be FPT by Guo and…

Discrete Mathematics · Computer Science 2009-02-09 Nicolas Bousquet , Jean Daligault , Stephan Thomasse , Anders Yeo

Maxmin trees are labeled trees with the property that each vertex is either a local maximum or a local minimum. Such trees were originally introduced by Postnikov, who gave a formula to count them and different combinatorial interpretations…

Combinatorics · Mathematics 2019-02-06 William Dugan , Sam Glennon , Paul E. Gunnells , Einar Steingrimsson

A graph $G=(V,E)$ is a $k$-leaf power if there is a tree $T$ whose leaves are the vertices of $G$ with the property that a pair of leaves $u$ and $v$ induce an edge in $G$ if and only if they are distance at most $k$ apart in $T$. For $k\le…

Combinatorics · Mathematics 2024-07-03 Max Dupré la Tour , Manuel Lafond , Ndiamé Ndiaye , Adrian Vetta

In this paper, we present a complete characterization of mutual-visibility sets in trees. It is shown that a subset $S$ is a mutual-visibility set of a tree $T$ if and only if it coincides with the set of leaves of the Steiner subtree…

Combinatorics · Mathematics 2026-05-20 Tonny K B , Shikhi M

We say that a finitely generated group $G$ has property (QT) if it acts isometrically on a finite product of quasi-trees so that orbit maps are quasi-isometric embeddings. A quasi-tree is a connected graph with path metric quasi-isometric…

Group Theory · Mathematics 2020-10-15 Mladen Bestvina , Kenneth Bromberg , Koji Fujiwara

A contemporary and fundamental problem faced by many evolutionary biologists is how to puzzle together a collection $\mathcal P$ of partial trees (leaf-labelled trees whose leaves are bijectively labelled by species or, more generally,…

Combinatorics · Mathematics 2007-09-04 S. Grünewald , K. T. Huber , Q. Wu

We construct the ordinary irreducible representations of the group of automorphisms of a finite rooted tree and we get a natural parametrization of them. To achieve this goals, we introduce and study the combinatorics of tree compositions,…

Representation Theory · Mathematics 2025-04-15 Fabio Scarabotti

We study power-set operations on classes of trees and tree algebras. Our main result consists of a distributive law between the tree monad and the upwards-closed power-set monad, in the case where all trees are assumed to be linear. For…

Formal Languages and Automata Theory · Computer Science 2024-02-14 Achim Blumensath

We show that if G is a finite group and f is a {0,1}-valued function on G with Fourier algebra norm at most M then f may be computed by a coset decision tree (that is a decision tree in which at each vertex we query membership of a given…

Classical Analysis and ODEs · Mathematics 2019-11-11 Tom Sanders