Results 81 to 90 of about 69,865 (208)

On Oriented Colourings of Graphs on Surfaces

Journal of Graph Theory, Volume 112, Issue 4, Page 357-369, August 2026.
ABSTRACT For an oriented graph G, the least number of colours required to oriented colour G is called the oriented chromatic number of G and denoted χ o ( G ). For a non‐negative integer g let χ o ( g ) be the least integer such that χ o ( G ) ≤ χ o ( g ) for every oriented graph G with Euler genus at most g.
Alexander Clow
wiley   +1 more source

Degree Powers in Graphs with Forbidden Subgraphs [PDF]

The Electronic Journal of Combinatorics, 2004
For every real $p>0$ and simple graph $G,$ set $$ f\left( p,G\right) =\sum_{u\in V\left( G\right) }d^{p}\left( u\right) , $$ and let $\phi\left( r,p,n\right) $ be the maximum of $f\left( p,G\right) $ taken over all $K_{r+1}$-free graphs $G$ of order $n.$ We prove that, if $0 < p < r,$ then$$ \phi\left( r,p,n\right) =f\left( p,T_{r ...
Béla Bollobás, Vladimir Nikiforov 0001
openaire   +3 more sources

Edge‐Length Preserving Embeddings of Graphs Between Normed Spaces

Journal of Graph Theory, Volume 112, Issue 4, Page 491-506, August 2026.
ABSTRACT The concept of graph embeddability, initially formalized by Belk and Connelly and later expanded by Sitharam and Willoughby, extends the question of embedding finite metric spaces into a given normed space. A finite simple graph G = ( V , E ) is said to be ( X , Y )‐embeddable if any set of induced edge lengths from an embedding of G into a ...
Sean Dewar, Eleftherios Kastis, Derek Kitson, William Sims   +3 more
wiley   +1 more source

A Forbidden Subgraph Characterization Problem and a Minimal-Element Subset of Universal Graph Classes [PDF]

, 2004
The direct sum of a finite number of graph classes H_1, ..., H_k is defined as the set of all graphs formed by taking the union of graphs from each of the H_i. The join of these graph classes is similarly defined as the set of all graphs formed by taking
Barrus, Michael D.
core  

Pairwise Imitation and Tournament Graphs

International Economic Review, Volume 67, Issue 3, Page 937-955, August 2026.
ABSTRACT This paper investigates strategic dynamics under the behavioral rule of pairwise interact and imitate (PII), which requires minimal information and emphasizes outperforming opponents in pairwise interactions. We characterize PII using weak tournament graphs and, for a broad class of dynamics, establish a one‐shot stability result for ...
Sung‐Ha Hwang, Philip R. Neary, Jonathan Newton, Ryoji Sawa   +3 more
wiley   +1 more source

On a Ramsey–Turán variant of Roth's theorem

Bulletin of the London Mathematical Society, Volume 58, Issue 8, August 2026.
Abstract A classical theorem of Roth states that the maximum size of a solution‐free set of a homogeneous linear equation L$\mathcal {L}$ in Fp$\mathbb {F}_p$ is o(p)$o(p)$ if and only if the sum of the coefficients of L$\mathcal {L}$ is 0. In this paper, we prove a Ramsey–Turán variant of Roth's theorem, with respect to a natural notion of “structured”
Matija Bucić, Micha Christoph, Jaehoon Kim, Hyunwoo Lee, Varun Sivashankar   +4 more
wiley   +1 more source

Forbidden family of Ph-magic graphs

Electronic Journal of Graph Theory and Applications
Let G be a simple, finite, and undirected graph and H be a subgraph of G. The graph G admits an H-covering if every edge in G belongs to a subgraph isomorphic to H.
Tita Khalis Maryati, Fawwaz Fakhrurrozi Hadiputra, A. N. M. Salman   +2 more
doaj   +1 more source

Finding an almost perfect matching in a hypergraph avoiding forbidden submatchings

Journal of the London Mathematical Society, Volume 114, Issue 2, August 2026.
Abstract In 1973, Erdős conjectured the existence of high girth (n,3,2)$(n,3,2)$‐Steiner systems. Recently, Glock, Kühn, Lo, and Osthus and independently Bohman and Warnke proved the approximate version of Erdős' conjecture. Recently, Kwan, Sah, Sawhney, and Simkin proved Erdős' conjecture.
Michelle Delcourt, Luke Postle
wiley   +1 more source

How to see the forest despite the trees

Journal of the London Mathematical Society, Volume 114, Issue 2, August 2026.
Abstract One of the major starting points of discrete optimization is the theorem of Nash‐Williams and Tutte on the existence of k$k$ disjoint spanning trees of a graph, along with its counterpart on the existence of k$k$ forests covering all edges of the graph.
Erika Bérczi‐Kovács, András Frank
wiley   +1 more source

R ( 5 , 5 ) ≤ 46

Journal of Graph Theory, Volume 112, Issue 3, Page 198-208, July 2026.
ABSTRACT We prove that the Ramsey number R ( 5 , 5 ) is less than or equal to 46. The proof uses a combination of linear programming and checking a large number of cases by computer. All of the computational parts of the proof were independently implemented by both authors, with consistent results.
Vigleik Angeltveit, Brendan D. McKay
wiley   +1 more source