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Triangle-Free Process and the Ramsey Number $R(3,k)$ [Pehme köide]

  • Formaat: Paperback / softback, 125 pages, kõrgus x laius: 254x178 mm, kaal: 254 g
  • Sari: Memoirs of the American Mathematical Society
  • Ilmumisaeg: 30-Apr-2020
  • Kirjastus: American Mathematical Society
  • ISBN-10: 1470440717
  • ISBN-13: 9781470440718
  • Formaat: Paperback / softback, 125 pages, kõrgus x laius: 254x178 mm, kaal: 254 g
  • Sari: Memoirs of the American Mathematical Society
  • Ilmumisaeg: 30-Apr-2020
  • Kirjastus: American Mathematical Society
  • ISBN-10: 1470440717
  • ISBN-13: 9781470440718
The areas of Ramsey theory and random graphs have been closely linked ever since Erdos's famous proof in 1947 that the ``diagonal'' Ramsey numbers $R(k)$ grow exponentially in $k$. In the early 1990s, the triangle-free process was introduced as a model which might potentially provide good lower bounds for the ``off-diagonal'' Ramsey numbers $R(3,k)$. In this model, edges of $K_n$ are introduced one-by-one at random and added to the graph if they do not create a triangle; the resulting final (random) graph is denoted $G_n,\triangle $. In 2009, Bohman succeeded in following this process for a positive fraction of its duration, and thus obtained a second proof of Kim's celebrated result that $R(3,k) = \Theta \big ( k^2 / \log k \big )$. In this paper the authors improve the results of both Bohman and Kim and follow the triangle-free process all the way to its asymptotic end.
Chapter 1 Introduction
1(6)
1.1 Random graph processes
2(1)
1.2 The triangle-free process
2(5)
Chapter 2 An overview of the proof
7(8)
Chapter 3 Martingale bounds: The line of peril and the line of death
15(12)
3.1 The line of peril and the line of death
16(2)
3.2 A general lemma
18(3)
3.3 The events X(m), Y(m), Z(m) and Q(m)
21(2)
3.4 Tracking Xe
23(4)
Chapter 4 Tracking everything else
27(40)
4.1 Building sequences
30(5)
4.2 Self-correction
35(5)
4.3 Creating and destroying copies of F
40(5)
4.4 Balanced non-tracking graph structures
45(11)
4.5 Bounding the maximum change in Nφ(F)
56(4)
4.6 The land before time t = ω
60(3)
4.7 Proof of Theorem 4.1
63(4)
Chapter 5 Tracking Ye, and mixing in the Y-graph
67(22)
5.1 Mixing inside open neighbourhoods
69(4)
5.2 Mixing in the whole Y-graph
73(2)
5.3 Creating and destroying σ-walks
75(2)
5.4 Self-correction
77(9)
5.5 The Lines of Peril and Death
86(3)
Chapter 6 Whirlpools and Lyapunov functions
89(6)
6.1 Whirlpools
89(2)
6.2 Lyapunov functions
91(3)
6.3 The proof of Theorems 2.1, 2.4, 2.5, 2.7 and 2.11
94(1)
Chapter 7 Independent sets and maximum degrees in Gn,Δ
95(26)
7.1 A sketch of the proof
95(1)
7.2 Partitioning the bad events
96(2)
7.3 The events A(S, δ) and A'(S, δ)
98(2)
7.4 The events B(S, δ) ∩ D(S, δ)c and B'(S, δ) ∩ D(S, δ)c
100(5)
7.5 The events C(S, δ) and C'(S, δ)
105(8)
7.6 The event D(S, δ)
113(6)
7.7 The proof of Propositions 7.1 and 7.2
119(2)
Acknowledgements 121(2)
Bibliography 123
Gonzalo Fiz Pontiveros, Instituto Nacional de Matematica Pura e Aplicada (IMPA), Rio de Janeiro, Brasil

Simon Griffiths, Instituto Nacional de Matematica Pura e Aplicada (IMPA), Rio de Janeiro, Brasil

Robert Morris, Instituto Nacional de Matematica Pura e Aplicada (IMPA), Rio de Janeiro, Brasil