Title
Thresholds and Expectation-Thresholds of Monotone Properties with Small Minterms
Abstract
Let N be a finite set, let p epsilon (0, 1), and let N-p denote a random binomial subset of N where every element of N is taken to belong to the subset independently with probability p. This defines a product measure mu(p) on the power set of N, where mu(p) := Pr[N-p epsilon A] for A subset of 2(N). In this paper we study monotone (upward-closed) families A for which all minimal sets in A have size at most k, for some positive integer k. We prove that for such a family mu(p)(A)/p(k) is a decreasing function, which implies a uniform bound on the coarseness of the thresholds of such families. We also prove a structure theorem which enables one to identify in A either a substantial subfamily A(0) for which the first moment method gives a good approximation of its measure, or a subfamily which can be well approximated by a family with all minimal sets of size strictly smaller than k. Finally, we relate the (fractional) expectation threshold and the probability threshold of such a family, using linear programming duality. This is related to the threshold conjecture of Kahn and Kalai.
Year
Venue
Field
2015
ELECTRONIC JOURNAL OF COMBINATORICS
Structured program theorem,Integer,Discrete mathematics,Combinatorics,Product measure,Finite set,Duality (optimization),Power set,Conjecture,Mathematics,Monotone polygon
DocType
Volume
Issue
Journal
22
2.0
ISSN
Citations 
PageRank 
1077-8926
0
0.34
References 
Authors
0
3
Name
Order
Citations
PageRank
Ehud Friedgut144038.93
Jeff Kahn230442.26
Clara Shikhelman300.34