Turán problems for edge-ordered graphs

نویسندگان

چکیده

In this paper we initiate a systematic study of the Turán problem for edge-ordered graphs. A simple graph is called if its edges are linearly ordered. This notion allows us to graphs (and in particular their maximum number edges) when subgraph forbidden with specific edge-order but same underlying may appear different edge-order. We prove an Erd?s-Stone-Simonovits-type theorem graphs—we identify relevant parameter and call it order chromatic number. establish several important properties parameter. also numbers paths, star forests cycle length four. make strong connections Davenport-Schinzel theory, theory submatrices, show application discrete geometry.

برای دانلود باید عضویت طلایی داشته باشید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Turán Problems for Bipartite Graphs ∗

We consider an infinite version of the bipartite Turán problem. Let G be an infinite graph with V (G) = N, and let Gn be the n-vertex subgraph of G induced by the vertices {1, 2, . . . , n}. We show that if G is K2,t+1-free, then for infinitely many n, e(Gn) ≤ 0.471 √ tn3/2. Using the K2,t+1-free graphs constructed by Füredi, we construct an infinite K2,t+1-free graph with e(Gn) ≥ 0.23 √ tn3/2 ...

متن کامل

An Ordered Turán Problem for Bipartite Graphs

Let F be a graph. A graph G is F -free if it does not contain F as a subgraph. The Turán number of F , written ex(n, F ), is the maximum number of edges in an F -free graph with n vertices. The determination of Turán numbers of bipartite graphs is a challenging and widely investigated problem. In this paper we introduce an ordered version of the Turán problem for bipartite graphs. Let G be a gr...

متن کامل

Turán problems for integer-weighted graphs

A multigraph is (k, r)-dense if every k-set spans at most r edges. What is the maximum number of edges exN(n, k, r) in a (k, r)-dense multigraph on n vertices? We determine the maximum possible weight of such graphs for almost all k and r (e.g., for all r > k) by determining a constant m = m(k, r) and showing that exN(n, k, r) = m ( n 2 ) +O(n), thus giving a generalization of Turán’s theorem. ...

متن کامل

Extremal problems in ordered graphs

In this thesis we consider ordered graphs (that is, graphs with a fixed linear ordering on their vertices). We summarize and further investigations on the number of edges an ordered graph may have while avoiding a fixed forbidden ordered graph as a subgraph. In particular, we take a step toward confirming a conjecture of Pach and Tardos [12] regarding the number of edges allowed when the forbid...

متن کامل

Ramsey and Turán-type problems in bipartite geometric graphs

A = {(1, 0), (2, 0), . . . , (n, 0)}, B = {((1, 1), (2, 1), . . . , (n, 1)} and the edge ab is the line segment joining a ∈ A and b ∈ B in R. This model is essentially the same as the cyclic bipartite graphs and ordered bipartite graphs considered earlier by several authors. Subgraphs — paths, trees, double stars, matchings — are called non-crossing if they do not contain edges with common inte...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

ژورنال

عنوان ژورنال: Journal of Combinatorial Theory, Series B

سال: 2023

ISSN: ['0095-8956', '1096-0902']

DOI: https://doi.org/10.1016/j.jctb.2022.12.006