questions to John Hammersley on the use of numerical methods to analyze this model.

Broadbent and Hammersley introduced in their article of 1957 a mathematical model to model this phenomenon, that is percolation.

Computation of the critical parameter

For most infinite lattice graphs, cannot be calculated exactly, though in some cases there is an exact value. For example:

*for the square lattice in two dimensions, for bond percolation,