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Higher-rank graph generalisations of the Popescu-Poisson transform are constructed, allowing us to develop a dilation theory for higher rank operator tuples. These dilations are joint dilations of the families of operators satisfying…

Operator Algebras · Mathematics 2008-06-16 Adam Skalski , Joachim Zacharias

We consider $p$-orientations, which are defined to be orientations of $d$-regular graphs such that every vertex either has in-degree $p$ or out-degree $p$. These generalise the orientations considered in Jaeger's conjecture, where $d=4p+1$.…

Combinatorics · Mathematics 2026-04-27 Catherine Greenhill , Mikhail Isaev , Charles Lewis

A broader definition of generalized truncations of graphs is introduced followed by an exploration of some standard concepts and parameters with regard to generalized truncations.

Combinatorics · Mathematics 2020-07-10 Brian Alspach , Joshua B. Connor

Ortho-Radial drawings are a generalization of orthogonal drawings to grids that are formed by concentric circles and straight-line spokes emanating from the circles' center. Such drawings have applications in schematic graph layouts, e.g.,…

Discrete Mathematics · Computer Science 2017-03-20 Lukas Barth , Benjamin Niedermann , Ignaz Rutter , Matthias Wolf

In this paper, we extend the definition of cohomology associated to monotone graph properties, to encompass twisted functor coefficients. We introduce oriented matchings on graphs, and focus on their (twisted) cohomology groups. We…

Combinatorics · Mathematics 2022-03-08 Luigi Caputi , Daniele Celoria , Carlo Collari

In this paper, we study oriented bipartite graphs. In particular, we introduce "bitransitive" graphs. Several characterizations of bitransitive bitournaments are obtained. We show that bitransitive bitounaments are equivalent to acyclic…

Combinatorics · Mathematics 2021-03-16 Sandip Das , Prantar Ghosh , Shamik Ghosh , Sagnik Sen

An oriented graph is a directed graph without any cycle of length at most 2. To push a vertex of a directed graph is to reverse the orientation of the arcs incident to that vertex. Klostermeyer and MacGillivray defined push graphs which are…

Discrete Mathematics · Computer Science 2015-08-31 Sagnik Sen

We introduce a generalization of the notion of operad that we call a contractad, whose set of operations is indexed by connected graphs and whose composition rules are numbered by contractions of connected subgraphs. We show that many…

Algebraic Topology · Mathematics 2024-07-24 Denis Lyskov

The theory of graphons has proven to be a powerful tool in many areas of graph theory. In this paper, we introduce several foundational aspects of the theory of digraphons -- asymmetric two-variable functions that arise as limits of…

Combinatorics · Mathematics 2025-12-16 Jan Hladký , Petr Savický

The preference graph is a combinatorial representation of the structure of a normal-form game. Its nodes are the strategy profiles, with an arc between profiles if they differ in the strategy of a single player, where the orientation…

Computer Science and Game Theory · Computer Science 2025-02-07 Oliver Biggar , Iman Shames

We study finite graphs embedded in oriented surfaces by associating a polynomial to it. The tools used in developing a theory of such graph polynomials are algebraic topological while the polynomial itself is inspired from ideas arising in…

Combinatorics · Mathematics 2022-05-02 Somnath Basu , Dhruv Bhasin , Siddhartha Lal , Siddhartha Patra

In this paper we study the structure of $k$-transitive closures of directed paths and formulate several properties. Concept of $k$-transitive orientation generalize the traditional concept of transitive orientation of a graph.

Combinatorics · Mathematics 2014-12-24 Krzysztof Pszczoła

For fractals on Riemannian manifolds, the theory of iterated function systems often does not apply well directly, as fractal sets are often defined by relations that are multivalued or non-contractive. To overcome this difficulty, we…

Dynamical Systems · Mathematics 2024-12-19 Jie Liu , Sze-Man Ngai , Lei Ouyang

An ordered $r$-matching is an $r$-uniform hypergraph matching equipped with an ordering on its vertices. These objects can be viewed as natural generalisations of $r$-dimensional orders. The theory of ordered 2-matchings is well-developed…

Combinatorics · Mathematics 2025-03-19 Michael Anastos , Zhihan Jin , Matthew Kwan , Benny Sudakov

For integers \(r\ge 2\), \(t\ge 1\) and a real number \(a\in(3/2,2]\), we study the typical structure of oriented graphs and digraphs that do not contain a blow-up \(T_{r+1}^t\) of a transitive tournament. We prove that almost every…

Combinatorics · Mathematics 2026-05-26 Meili Liang , Yue Guan , Ruiling Zheng , Jianxi Liu

These lecture notes are a personal introduction to signed graphs, concentrating on the aspects that have been most persistently interesting to me. They are just a few corners of signed graph theory; I am leaving out a great deal. The…

Combinatorics · Mathematics 2016-10-18 Thomas Zaslavsky

Delta-matroid theory is often thought of as a generalization of topological graph theory. It is well-known that an orientable embedded graph is bipartite if and only if its Petrie dual is orientable. In this paper, we first introduce the…

Combinatorics · Mathematics 2020-03-05 Qi Yan , Xian'an Jin

It is a basic introduction to differential graded Lie algebras, Maurer-Cartan equation and associated deformation functors.

Algebraic Geometry · Mathematics 2007-05-23 Marco Manetti

An ordinal-valued metric taking its values in the set of all countable ordinals can be assigned to a metrizable set of nodes in a transfinite graph. Then, a variety of results concerning nodal eccentricities, radii, diameters, centers,…

Combinatorics · Mathematics 2007-05-23 A. H. Zemanian

We define the notions of Reidemeister torsion and analytic torsion for directed graphs by means of the path homology theory introduced by the authors in \cite{Grigoryan-Lin-Muranov-Yau2013, Grigoryan-Lin-Muranov-Yau2014,…

Combinatorics · Mathematics 2020-12-15 Alexander Grigor'yan , Yong Lin , Shing-Tung Yau