How frequently is a system of 2-linear Boolean equations solvable?
Abstract
We consider a random system of equations , , with the pairs from , a symmetric subset of . is chosen uniformly at random among all such subsets of a given cardinality ; alternatively with a given probability , independently of all other pairs. Also, given , for each , independently of all other . It is well known that, as passes through ( passes through , resp.), the underlying random graph , (, resp.) undergoes a rapid transition, from essentially a forest of many small trees to a graph with one large, multicyclic, component in a sea of small tree components. We should expect then that the solvability probability decreases precipitously in the vicinity of (), and indeed this probability is of order , for (, for , resp.). We show that in a near-critical phase (, resp.), , the system is solvable with probability asymptotic to , for some explicit function . Mike Molloy noticed that the Boolean system with is solvable iff the underlying graph is -colorable, and asked whether this connection might be used to determine an order of probability of -colorability in the near-critical case. We answer Mike's question affirmatively and show that probability of -colorability is , and asymptotic to at a critical phase , and for . (Submitted to Electronic Journal of Combinatorics on September 7, 2009.)
Cite
@article{arxiv.1005.1951,
title = {How frequently is a system of 2-linear Boolean equations solvable?},
author = {Boris Pittel and Ji-A Yeum},
journal= {arXiv preprint arXiv:1005.1951},
year = {2010}
}