On the Ramsey-Turán number with small s-independence number

Let $s$ be an integer, $f=f(n)$ a function, and $H$ a graph. Define the Ramsey-Tur\'an number $RT_s(n,H, f)$ as the maximum number of edges in an $H$-free graph $G$ of order $n$ with $\alpha_s(G) 0$ and $1/2<\delta< 1$, $RT_s(n,K_{s+1}, n^{\delta}) = \Omega(n^{1+\delta-\varepsilon})$ for all sufficiently large $s$. This is nearly optimal, since a trivial upper bound yields $RT_s(n,K_{s+1}, n^{\delta}) = O(n^{1+\delta})$. Furthermore, the range of $\delta$ is as large as possible. We also consider more general cases and find bounds on $RT_s(n,K_{s+r},n^{\delta})$ for fixed $r\ge2$. Finally, we discuss a phase transition of $RT_s(n, K_{2s+1}, f)$ extending some recent result of Balogh, Hu and Simonovits.

[1]  Svante Janson,et al.  Random graphs , 2000, Wiley-Interscience series in discrete mathematics and optimization.

[2]  Noga Alon,et al.  Constructive Bounds for a Ramsey-Type Problem , 1997, Graphs Comb..

[3]  Joseph A. Thas,et al.  Chapter 9 – Generalized Polygons , 1995 .

[4]  Michael Krivelevich,et al.  Bounding Ramsey Numbers through Large Deviation Inequalities , 1995, Random Struct. Algorithms.

[5]  Andrzej Dudek,et al.  On Generalized Ramsey Numbers for 3‐Uniform Hypergraphs , 2013, J. Graph Theory.

[6]  Endre Szemerédi,et al.  More results on Ramsey—Turán type problems , 1983, Comb..

[7]  Benny Sudakov,et al.  A New Lower Bound For A Ramsey-Type Problem , 2005, Comb..

[8]  Miklós Simonovits,et al.  Phase transitions in the Ramsey-Turán theory , 2013 .

[9]  Tom Bohman,et al.  Dynamic concentration of the triangle‐free process , 2013, Random Struct. Algorithms.

[10]  Benny Sudakov,et al.  Dependent random choice , 2009, Random Struct. Algorithms.

[11]  W. T. Gowers,et al.  A New Proof of Szemerédi's Theorem for Arithmetic Progressions of Length Four , 1998 .

[12]  Michael Krivelevich,et al.  Ks-Free Graphs Without Large Kr-Free Subgraphs , 1994, Combinatorics, Probability and Computing.

[13]  Benny Sudakov Large K r -free subgraphs in K s -free graphs and some other Ramsey-type problems , 2005 .

[14]  J. Maynard On the difference between consecutive primes , 2012, 1201.1787.

[15]  Peter Keevash,et al.  The early evolution of the H-free process , 2009, 0908.0429.

[16]  Benny Sudakov Afew remarks on Ramsey-Turan-type problems , 2003 .

[17]  Yufei Zhao,et al.  The critical window for the classical Ramsey-Turán problem , 2012, Comb..

[18]  Béla Bollobás,et al.  On a Ramsey-Turán type problem , 1976, Journal of combinatorial theory. Series B (Print).

[19]  JANOS BOLYAI,et al.  Some remarks on Ramsey ’ s and TurWs theorem , 2002 .

[20]  Gordon F. Royle,et al.  Algebraic Graph Theory , 2001, Graduate texts in mathematics.

[21]  Guy Wolfovitz,et al.  K4-free graphs without large induced triangle-free subgraphs , 2013, Comb..

[22]  J. Pintz,et al.  The Difference Between Consecutive Primes, II , 2001 .

[23]  Christopher M. Hartman Extremal problems in graph theory , 1997 .

[24]  Béla Bollobás,et al.  Random Graphs , 1985 .

[25]  Noga Alon,et al.  The Probabilistic Method , 2015, Fundamentals of Ramsey Theory.

[26]  James B. Shearer,et al.  A note on the independence number of triangle-free graphs , 1983, Discret. Math..

[27]  Miklós Simonovits,et al.  Turán-Ramsey Theorems and Kp-Independence Numbers , 1994, Combinatorics, Probability and Computing.

[28]  Andrzej Dudek,et al.  On Ks-free subgraphs in Ks+k-free graphs and vertex Folkman numbers , 2011, Comb..

[29]  Andrzej Dudek,et al.  On generalized Ramsey numbers of Erdős and Rogers , 2014, J. Comb. Theory, Ser. B.

[30]  Vojtech Rödl,et al.  On graphs with small Ramsey numbers , 2001, J. Graph Theory.

[31]  Benny Sudakov,et al.  Large Kr‐free subgraphs in Ks‐free graphs and some other Ramsey‐type problems , 2005, Random Struct. Algorithms.

[32]  Béla Bollobás,et al.  Graphs without large triangle free subgraphs , 1991, Discret. Math..

[33]  John Lenz,et al.  On the Ramsey-Turán numbers of graphs and hypergraphs , 2011, 1109.4428.

[34]  John Lenz,et al.  Some exact Ramsey–Turán numbers , 2011, 1109.4472.

[35]  Miklós Simonovits,et al.  Ramsey-Turán theory , 2001, Discret. Math..

[36]  Béla Bollobás,et al.  Extremal problems in graph theory , 1977, J. Graph Theory.

[37]  Gonzalo Fiz Pontiveros,et al.  The triangle-free process and R(3,k) , 2013 .

[38]  P. Cameron Combinatorics: Topics, Techniques, Algorithms , 1995 .

[39]  Paul Erdös,et al.  The Construction of Certain Graphs , 1966, Canadian Journal of Mathematics.