MathDB
percolation

Source:

March 3, 2011
probabilityprobability and stats

Problem Statement

suppose that 0p10\le p \le 1 and we have a wooden square with side length 11. in the first step we cut this square into 44 smaller squares with side length 12\frac{1}{2} and leave each square with probability pp or take it with probability 1p1-p. in the next step we cut every remaining square from the previous step to 44 smaller squares (as above) and take them with probability 1p1-p. it's obvios that at the end what remains is a subset of the first square. a) show that there exists a number 0<p0<10<p_0<1 such that for p>p0p>p_0 the probability that the remainig set is not empty is positive and for p<p0p<p_0 this probability is zero. b) show that for every p1p\neq 1 with probability 11, the remainig set has size zero. c) for this statement that the right side of the square is connected to the left side of the square with a path, write anything that you can.