Thresholds and Expectation Thresholds

Series: 
School of Mathematics Colloquium
Tuesday, March 13, 2012 - 11:05
1 hour (actually 50 minutes)
Location: 
Skiles 006
,  
Mathematics, Rutgers University
,  
Organizer: 
Thresholds for increasing properties are a central concern in probabilistic combinatorics and elsewhere. (An increasing property, say F, is a superset-closed family of subsets of some (here finite) set X; the threshold question for such an F asks, roughly, about how many random elements of X should one choose to make it likely that the resulting set lies in F? For example: about how many random edges from the complete graph K_n are typically required to produce a Hamiltonian cycle?) We'll discuss recent progress and lack thereof on a few threshold-type questions, and try to say something about a ludicrously general conjecture of G. Kalai and the speaker to the effect that there is always a pretty good naive explanation for a threshold being what it is.