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Topological deep learning is a rapidly growing field that pertains to the development of deep learning models for data supported on topological domains such as simplicial complexes, cell complexes, and hypergraphs, which generalize many…

Graphs with given k vertices generate an (acyclic) simplicial complex. We describe the homology of its quotient complex, formed by all connected graphs, and demonstrate its applications to the topology of braid groups, knot theory,…

Combinatorics · Mathematics 2014-09-23 V. A. Vassiliev

In this paper, we define and characterize signed interval graphs and bigraphs introducing the concept of negative interval. Also we have shown that these classes of graphs are respectively a generalization of well known classes of interval…

Discrete Mathematics · Computer Science 2022-06-14 Ashok Kumar Das , Indrajit Paul

A moplex is a natural graph structure that arises when lifting Dirac's classical theorem from chordal graphs to general graphs. While every non-complete graph has at least two moplexes, little is known about structural properties of graphs…

Combinatorics · Mathematics 2023-02-01 Clément Dallard , Robert Ganian , Meike Hatzel , Matjaž Krnc , Martin Milanič

The present work aims to exploit the interplay between the algebraic properties of rings and the graph-theoretic structures of their associated graphs. We introduce commutatively closed graphs and investigate properties of commutatively…

Rings and Algebras · Mathematics 2021-05-06 André Leroy , Mona Abdi

An interval graph is considered improper if and only if it has a representation such that an interval contains another interval. Previously these have been investigated in terms of balance and minimal forbidden interval subgraphs for the…

Combinatorics · Mathematics 2015-05-28 Jeffrey J. Beyerl , Wayne Wallace

We show that the discrete versions of the systolic inequality that estimate the number of vertices of a simplicial complex from below have substantial applications to graphs, the one-dimensional simplicial complexes. Almost directly they…

Combinatorics · Mathematics 2022-11-01 Alexander Kamal , Roman Karasev

In this paper, we investigate a family of graphs associated to collections of arcs on surfaces. These {\it multiarc graphs} naturally interpolate between arc graphs and flip graphs, both well studied objects in low dimensional geometry and…

Geometric Topology · Mathematics 2019-03-01 Hugo Parlier , Ashley Weber

In `A survey of two-graphs' \cite{Sei}, J.J. Seidel lays out the connections between simple graphs, two-graphs, equiangular lines and strongly regular graph. It is well known that there is a one-to-one correspondence between regular…

Combinatorics · Mathematics 2017-03-16 Thomas Hoffman , James Solazzo

Unit interval and interval complexes are higher-dimensional generalizations of unit interval and interval graphs, respectively. We show that strongly connected unit interval complexes are shellable with shellings induced by their unit…

Combinatorics · Mathematics 2024-11-14 Bennet Goeckner , Marta Pavelka

In 1969, Roberts introduced proper and unit interval graphs and proved that these classes are equal. Natural generalizations of unit interval graphs called $k$-length interval graphs were considered in which the number of different lengths…

Discrete Mathematics · Computer Science 2017-04-13 Pavel Klavík , Yota Otachi , Jiří Šejnoha

The recently introduced problem of extending partial interval representations asks, for an interval graph with some intervals pre-drawn by the input, whether the partial representation can be extended to a representation of the entire…

Discrete Mathematics · Computer Science 2014-08-26 Pavel Klavík , Jan Kratochvíl , Yota Otachi , Ignaz Rutter , Toshiki Saitoh , Maria Saumell , Tomáš Vyskočil

In this note we prove that every closed graph $G$ is up to isomorphism a proper interval graph. As a consequence we obtain that there exist linear-time algorithms for closed graph recognition.

Combinatorics · Mathematics 2012-11-27 Marilena Crupi , Giancarlo Rinaldo

We prove a general large sieve statement in the context of random walks on subgraphs of a given graph. This can be seen as a generalization of previously known results where one performs a random walk on a group enjoying a strong spectral…

Group Theory · Mathematics 2017-01-09 Florent Jouve , Jean-Sébastien Sereni

Interval and proper interval graphs are very well-known graph classes, for which there is a wide literature. As a consequence, some generalizations of interval graphs have been proposed, in which graphs in general are expressed in terms of…

Discrete Mathematics · Computer Science 2023-04-04 Flavia Bonomo-Braberman , Fabiano S. Oliveira , Moysés S. Sampaio , Jayme L. Szwarcfiter

A graph $G$ is said to be chordal if it has no induced cycles of length four or more. In a recent preprint Culbertson, Guralnik, and Stiller give a new characterization of chordal graphs in terms of sequences of what they call…

Combinatorics · Mathematics 2021-02-25 Anton Dochtermann

This is an exposition of some new results on associated primes and the depth of different kinds of powers of monomial ideals in order to show a deep connection between commutative algebra and some objects in combinatorics such as simplicial…

Commutative Algebra · Mathematics 2018-09-21 Le Tuan Hoa

A graph is reconstructible if it is determined up to isomorphism by the multiset of its proper induced subgraphs. The reconstruction conjecture postulates that every graph of order at least 3 is reconstructible. We show that interval graphs…

Combinatorics · Mathematics 2026-05-13 Irene Heinrich , Masashi Kiyomi , Yota Otachi , Pascal Schweitzer

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

Schubert polynomials were introduced in the context of the geometry of flag varieties. This paper investigates some of the connections not yet understood between several combinatorial structures for the construction of Schubert polynomials;…

Combinatorics · Mathematics 2007-05-23 Cristian Lenart