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We generalise structure tree theory, which is based on removing finitely many edges, to removing finitely many vertices. This gives a significant generalization of Tutte's tree decomposition of 2-connected graphs into 3-connected blocks.…

Group Theory · Mathematics 2015-01-05 M. J. Dunwoody , B. Krön

Separation Logic is a widely used formalism for describing dynamically allocated linked data structures, such as lists, trees, etc. The decidability status of various fragments of the logic constitutes a long standing open problem. Current…

Logic in Computer Science · Computer Science 2013-04-02 Radu Iosif , Adam Rogalewicz , Jiri Simacek

Common meadows are commutative and associative algebraic structures with two operations (addition and multiplication) with additive and multiplicative identities and for which inverses are total. The inverse of zero is an error term…

Rings and Algebras · Mathematics 2024-06-10 João Dias , Bruno Dinis

We study a class of combinatorial objects that we call "decorated trees". These consist of vertices, arrows and edges, where each edge is decorated by two integers (one near each of its endpoints), each arrow is decorated by an integer, and…

Algebraic Geometry · Mathematics 2024-10-08 Pierrette Cassou-Noguès , Daniel Daigle

Tiered trees were introduced as a combinatorial object for counting absolutely indecomposable representation of certain quivers and torus orbit of certain homogeneous variety. In this paper, we define a bijection between the set of…

Combinatorics · Mathematics 2024-08-07 Biswadeep Bagchi , Srinibas Swain

We consider absolutely free nonassociative algebras and, more generally, absolutely free algebras with (maybe infinitely) many multilinear operations. Such algebras are described in terms of labeled reduced planar rooted trees. This allows…

Rings and Algebras · Mathematics 2009-03-25 Vesselin Drensky , Ralf Holtkamp

We compare two known methods of extending a complex, unital, commutative normed algebra so as to include solutions to sets of monic polynomials over the original algebra. (One of these is a generalisation of a construction from the thesis…

Functional Analysis · Mathematics 2007-05-23 Thomas Dawson

We explore from an algebraic viewpoint the properties of the tree languages definable with a first-order formula involving the ancestor predicate, using the description of these languages as those recognized by iterated block products of…

Formal Languages and Automata Theory · Computer Science 2018-12-06 Martin Beaudry

The monadic second-order theory of trees allows quantification over elements and over arbitrary subsets. We classify the class of trees with respect to the question: does a tree T have a definable choice function (by a monadic formula with…

Logic · Mathematics 2009-09-25 Shmuel Lifsches , Saharon Shelah

Any function can be constructed using a hierarchy of simpler functions through compositions. Such a hierarchy can be characterized by a binary rooted tree. Each node of this tree is associated with a function which takes as inputs two…

Machine Learning · Computer Science 2019-10-23 Roozbeh Farhoodi , Khashayar Filom , Ilenna Simone Jones , Konrad Paul Kording

An automaton is called reachable if every state is reachable from the initial state. This notion has been generalized coalgebraically in two ways: first, via a universal property on pointed coalgebras, namely, that a reachable coalgebra has…

Logic in Computer Science · Computer Science 2026-01-23 Thorsten Wißmann , Bálint Kocsis , Jurriaan Rot , Ruben Turkenburg

We prove that every oriented tree on $n$ vertices with bounded maximum degree appears as a spanning subdigraph of every directed graph on $n$ vertices with minimum semidegree at least $n/2+o(n)$. This can be seen as a directed graph…

Combinatorics · Mathematics 2026-05-20 Richard Mycroft , Tássio Naia

We prove several criteria for quasi-isometry between non-locally-finite graphs and their structure trees. Results of M\"oller in \cite{moeller92ends2} for locally finite and transitive graphs are generalized. We also give a criterion which…

Combinatorics · Mathematics 2007-05-23 Bernhard Krön

Arboreal networks are a generalization of rooted trees, defined by keeping the tree-like structure, but dropping the requirement for a single root. Just as the class of cographs is precisely the class of undirected graphs that can be…

Combinatorics · Mathematics 2025-02-13 Guillaume E. Scholz

In the setting of constructive mathematics, we suggest and study a framework for decidability of properties, which allows for finer distinctions than just "decidable, semidecidable, or undecidable". We work in homotopy type theory and use…

Logic in Computer Science · Computer Science 2026-05-14 Tom de Jong , Nicolai Kraus , Aref Mohammadzadeh , Fredrik Nordvall Forsberg

Connection matrices for graph parameters with values in a field have been introduced by M. Freedman, L. Lov{\'a}sz and A. Schrijver (2007). Graph parameters with connection matrices of finite rank can be computed in polynomial time on graph…

Combinatorics · Mathematics 2014-05-13 Nadia Labai , Johann A. Makowsky

Much information about a graph can be obtained by studying its spanning trees. On the other hand, a graph can be regarded as a 1-dimensional cell complex, raising the question of developing a theory of trees in higher dimension. As observed…

Combinatorics · Mathematics 2015-06-24 Art M. Duval , Caroline J. Klivans , Jeremy L. Martin

The tree-depth problem can be seen as finding an elimination tree of minimum height for a given input graph $G$. We introduce a bicriteria generalization in which additionally the width of the elimination tree needs to be bounded by some…

Data Structures and Algorithms · Computer Science 2021-05-31 Piotr Borowiecki , Dariusz Dereniowski , Dorota Osula

This paper deals with graph automaton groups associated with trees and some generalizations. We start by showing some algebraic properties of tree automaton groups. Then we characterize the associated semigroup, proving that it is…

Group Theory · Mathematics 2023-04-10 Matteo Cavaleri , Daniele D'Angeli , Alfredo Donno , Emanuele Rodaro

Certain families of combinatorial objects admit recursive descriptions in terms of generating trees: each node of the tree corresponds to an object, and the branch leading to the node encodes the choices made in the construction of the…