Probabiity of a graph containg hamiltonian cycle with given probabily for and edge between any two vertices.

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Consider a non-oriented graph with n vertices: {1 ... n}.

Let $ p \in [0,1]$ is the probability of having an edge between any two vertices. The probability of having an edge is the same for any two vertices.

So I have two tasks:

  • a) Find the probability of having a hamiltonian cycle in the graph.
  • b) What is the probability of havin a hamiltonian cycle if we know that $(1)-(2) \dots - (k)$ is a path in the graph.

My attempt for a):

So we have (n - 1)! different options for a hamiltonian cycle.

The probability of having (for example) this ham cycle: $(1)-(2) \dots (n) - (1)$ is $p^{n}$

So the probability that the graph DOES NOT contain a ham cycle is $1 - (p^n)^{(n-1)!} $

But the problem is that I consider that the existence of the different ham paths are indpendent, which is obviously not true.

Any tips?