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By finding orthogonal representation for a family of simple connected called $\delta$-graphs it is possible to show that $\delta$-graphs satisfy delta conjecture. An extension of the argument to graphs of the form…

Combinatorics · Mathematics 2018-06-20 Pedro Díaz Navarro

The graph reconstruction conjecture states that all graphs on at least three vertices are determined up to isomorphism by their deck. In this paper, a general framework for this problem is proposed to simply explain the reconstruction of…

Combinatorics · Mathematics 2018-10-26 Ameneh Farhadian

The graph reconstruction conjecture asserts that every simple graph on at least three vertices is uniquely determined by its deck of vertex-deleted subgraphs. In this expository article we survey the conjecture and present an…

Combinatorics · Mathematics 2026-04-21 Emilie Dufresne , Gabriela Jeronimo , Jenny Kenkel , Haydee Lindo , Nelly Villamizar

We describe a simple algorithm based on a Markov chain process to generate simply connected acyclic directed graphs over a fixed set of vertices. This algorithm is an extension of a previous one, designed to generate acyclic digraphs, non…

Discrete Mathematics · Computer Science 2007-05-23 Guy Melancon , Fabrice Philippe

We show that for a sequence of random graphs Brouwer's conjecture holds true with probability tending to one as the number of vertices tends to infinity. Surprisingly, it was found that a similar statement holds true for weighted graphs…

Combinatorics · Mathematics 2019-06-14 Israel Rocha

A biased graph is a graph $G$, together with a distinguished subset $\mathcal{B}$ of its cycles so that no Theta-subgraph of $G$ contains precisely two cycles in $\mathcal{B}$. A large number of biased graphs can be constructed by choosing…

Combinatorics · Mathematics 2020-12-14 Peter Nelson , Jorn van der Pol

A conjecture of Barnette states that every 3-connected cubic bipartite plane graph has a Hamilton cycle, which is equivalent to the statement that every simple even plane triangulation admits a partition of its vertex set into two subsets…

Combinatorics · Mathematics 2012-08-22 Jan Florek

In this paper, we count acyclic and strongly connected uniform directed labeled hypergraphs. For these combinatorial structures, we introduce a specific generating function allowing us to recover and generalize some results on the number of…

Combinatorics · Mathematics 2020-05-28 Vonjy Rasendrahasina , Vlady Ravelomanana

The stack number of a directed acyclic graph $G$ is the minimum $k$ for which there is a topological ordering of $G$ and a $k$-coloring of the edges such that no two edges of the same color cross, i.e., have alternating endpoints along the…

Combinatorics · Mathematics 2025-10-29 Paul Jungeblut , Laura Merker , Torsten Ueckerdt

For a finite simple graph $G$, the bunkbed graph $G^\pm$ is defined to be the product graph $G\square K_2$. We will label the two copies of a vertex $v\in V(G)$ as $v_-$ and $v_+$. The bunkbed conjecture, posed by Kasteleyn, states that for…

Combinatorics · Mathematics 2023-02-02 Lawrence Hollom

In this paper, a proof of the cycle double cover conjecture is presented. The cycle double cover conjecture purports that if a graph is bridgeless, then there exists a list of cycles in the graph such that every edge in the graph appears in…

Combinatorics · Mathematics 2014-04-08 P. Clarke

We construct, for every $d \geq 3$, a $d$-regular acyclic measurably bipartite graphing that admits no measurable perfect matching, resolving a problem of Kechris and Marks. A dense variant of our construction yields a coupling of two…

Combinatorics · Mathematics 2024-10-11 Gábor Kun

Here we prove that Reed Conjecture is valid for {P5, Flag_Complement}-free graphs where FlagComplement is the complement of the Flag graph. Some of the known results follow as corollaries to our result. Reed conjecture is still open in…

Combinatorics · Mathematics 2017-06-27 Medha Dhurandhar

We construct the geometric Langlands functor in one direction (from the automorphic to the spectral side) in characteristic zero settings (i.e., de Rham and Betti). We prove that various forms of the conjecture (de Rham vs Betti, restricted…

Algebraic Geometry · Mathematics 2025-10-02 Dennis Gaitsgory , Sam Raskin

Two conjectures recently proposed by one of the authors are disproved

Metric Geometry · Mathematics 2011-05-25 P. G. L. Porta Mana , P. G. Lewis

We present a construction of 2-step nilpotent Lie algebras using labeled directed simple graphs, which allows us to give a criterion to detect certain ideals and subalgebras by finding special subgraphs. We prove that if a label occurs only…

Differential Geometry · Mathematics 2023-08-08 Mauricio Godoy Molina , Diego Lagos

The existence of an infinite simple boundedly generated 2-generated group and the existence of a boundedly simple 2-generated group containing a free non-cyclic subgroup are proved.

Group Theory · Mathematics 2022-03-28 Alexey Muranov

In this paper, we introduce the zero divisor graph of a multiplicative lattice. We provide a counter example to Beck's conjecture for multiplicative lattices. Further, we prove that Beck's conjecture is true for reduced multiplicative…

Commutative Algebra · Mathematics 2013-10-18 Vinayak Joshi , Sachin Sarode

Berge Conjecture states that every bridgeless cubic graph has 5 perfect matchings such that each edge is contained in at least one of them. In this paper, we show that Berge Conjecture holds for two classes of cubic graphs, cubic graphs…

Combinatorics · Mathematics 2016-03-01 Wuyang Sun

We prove that for every $n$, there is a graph $G$ with $\chi(G) \geq n$ and $\omega(G) \leq 3$ such that every induced subgraph $H$ of $G$ with $\omega(H) \leq 2$ satisfies $\chi(H) \leq 4$. This disproves a well-known conjecture. Our…

Combinatorics · Mathematics 2022-09-16 Alvaro Carbonero , Patrick Hompe , Benjamin Moore , Sophie Spirkl