Each function has two transition matrices
Each function is symmetric, so its two matrices identical
Each function has opposite (e.g. AND and NAND)
So mean matrix has the same value at every element
M1 is independent of u0
M1 is irreducible, doubly stochastic, with non-zero diagonal
Output of random function independent of inputs and random
Since the coefficients p' sum to 1, this is true for every Mi.
Output of whole tree random regardless of size