What is the expected number of neighbors of a vertex in a random digraph $D (n,p)$?
The degree of a vertex in a digraph is defined to be the minimum of in-degree and out-degree of that vertex.
If $X$ is the random variable that counts neighbors of a vertex $v$, then $x=\min \{x^+,x^-\}$, where $x^+$ and $x^-$ are random variables that count out-neighbors and in-neighbors of $v$.
Since both $x^+$ and $x^-$ are binomial random variables, it is easy to find CDF, but I am still not sure how to use that to find the expected number of neighbors.
Let x be the number of neighbors of a vertex v in a random digraph D (n,p) . Then E (X)= (n-1)[1-(1-p)^2]. I think this works correctly. I just figured this out.