THE PROBABILISTIC
METHOD
THE PROBABILISTIC
METHOD
Third edition, September 2007, Tel Aviv and New York
Noga Alon,
School of Mathematics,
Raymond and Beverly Sackler Faculty of Exact Sciences,
Tel Aviv University,
Tel Aviv, Israel.
Joel H. Spencer,
Courant Institute of Mathematical Sciences,
New York University,
New York, USA
A Wiley-Interscience Publication
JOHN WILEY & SONS, INC.
New York / Chichester / Weinheim / Brisbane / Singapore / Toronto
To Nurit and Mary Ann
Contents
Dedication
Preface
Acknowledgments
Part I METHODS
1 The Basic Method
The Probabilistic Method
1.1
1.2 Graph Theory
1.3 Combinatorics
1.4 Combinatorial Number Theory
1.5 Disjoint Pairs
1.6
Exercises
The Probabilistic Lens: The Erd ˝os–Ko–Rado Theorem
2 Linearity of Expectation
2.1
Basics
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CONTENTS
Splitting Graphs
Two Quickies
Balancing Vectors
2.2
2.3
2.4
2.5 Unbalancing Lights
2.6 Without Coin Flips
2.7
Exercises
The Probabilistic Lens: Br´egman’s Theorem
3 Alterations
Ramsey Numbers
Independent Sets
3.1
3.2
3.3 Combinatorial Geometry
3.4
3.5
3.6 Continuous Time
3.7
Packing
Recoloring
Exercises
The Probabilistic Lens: High Girth and High
Chromatic Number
4 The Second Moment
Basics
4.1
4.2 Number Theory
4.3 More Basics
4.4
Random Graphs
4.5 Clique Number
4.6 Distinct Sums
4.7
4.8
The R¨odl Nibble
Exercises
The Probabilistic Lens: Hamiltonian Paths
5 The Local Lemma
The Lemma
Property B and Multicolored Sets of Real Numbers
Lower Bounds for Ramsey Numbers
A Geometric Result
The Linear Arboricity of Graphs
5.1
5.2
5.3
5.4
5.5
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