A sharper threshold for bootstrap percolation in two dimensions (Q438962)

The paper deals with two-dimensional bootstrap percolation, which can be interpreted as a monotone version of the Ising model on a square of size \(n\times n\), with sites initially infected independently with probability \(p\). The smallest \(p\) for which the probability that the entire square is eventually infected exceeds \(1/2\) is called the critical probability. The authors sharpen Holroyd's result of the sharp first-order approximation for the critical probability, determining the second term in the expansion up to a poly-iterated logarithmic factor.