𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Extremal problems for directed graphs

✍ Scribed by W.G Brown; P Erdös; M Simonovits


Publisher
Elsevier Science
Year
1973
Tongue
English
Weight
858 KB
Volume
15
Category
Article
ISSN
0095-8956

No coin nor oath required. For personal study only.


📜 SIMILAR VOLUMES


On quadrilaterals in layers of the cube
✍ Schelp, Richard H.; Thomason, Andrew 📂 Article 📅 2000 🏛 John Wiley and Sons 🌐 English ⚖ 286 KB 👁 2 views

Erdős has conjectured that every subgraph of the n-cube Q n having more than (1/2+o(1))e(Q n ) edges will contain a 4-cycle. In this note we consider 'layer' graphs, namely, subgraphs of the cube spanned by the subsets of sizes k -1, k and k + 1, where we are thinking of the vertices of Q n as being

Minimizer graphs for a class of extremal
✍ Dan Ismailescu; Dan Stefanica 📂 Article 📅 2002 🏛 John Wiley and Sons 🌐 English ⚖ 93 KB 👁 2 views

## Abstract We consider the family of graphs with a fixed number of vertices and edges. Among all these graphs, we are looking for those minimizing the sum of the square roots of the vertex degrees. We prove that there is a unique such graph, which consists of the largest possible complete subgraph

Another extremal problem for Turan graph
✍ Bruce Hedman 📂 Article 📅 1987 🏛 Elsevier Science 🌐 English ⚖ 207 KB

We consider only finite, undirected graphs without loops or multiple edges. A clique of a graph G is a maximal complete subgraph of G. The clique number w(G) is the number of vertices in the largest clique of G. This note addresses the foflowing question: Which graphs G on n vertices with w(G) = r h

On some extremal problems on r-graphs
✍ P. Erdös 📂 Article 📅 1971 🏛 Elsevier Science 🌐 English ⚖ 499 KB

Abslract. Denote by @)(n; k) an ~-graph of n vcrtieca and k r-tuples. Turin's classical problem states: Detomline the smailcst integer f(n;r, I) so that cvcry G%; f(n; r, I)) contains a K@)(I). Tur&n determined f (n; r, I) for r = 2, but nothing is known for r > ?. Put lim,,f(n; t, O/(y) = c,,~ The

Extremal graphs for homomorphisms
✍ Jonathan Cutler; A. J. Radcliffe 📂 Article 📅 2011 🏛 John Wiley and Sons 🌐 English ⚖ 219 KB

The study of graph homomorphisms has a long and distinguished history, with applications in many areas of graph theory. There has been recent interest in counting homomorphisms, and in particular on the question of finding upper bounds for the number of homomorphisms from a graph G into a fixed imag