Hi All, My question is more academic than technical. The question is about interpretation of Poisson curve. I am using it to assess scale-free nature of degree distribution. Can you please briefly describe what is meant by the Poisson curve when you give it your range of k-neighbour data which apparently follows power-law (or does otherwise). The code I am using within the xyplot.panel to plot the Poisson curve follows. y is the degrees vector. kfreq <- table(y); # compute frequency hash table of y, the degrees k <- 1:max(y) for (i in k) { ichar <- as.character(i) # convert to match the names(freq), the character-based hash key of freq, which is degree-value if (!(ichar %in% names(kfreq))) kfreq[ichar] <- 0 } sortedkeys <- as.character(k) kfreq <- kfreq[sortedkeys] pk <- kfreq / length(y) panel.xyplot(col="blue", k, pk) #overlaying the poisson distribution poissonk <- ppois(k, lambda = mean(y), lower.tail = FALSE) # lower.tail: if TRUE (default), probabilities are P[X <= x], otherwise, P[X > x] panel.xyplot(col="red", k, poissonk) Regrads, Fayez GCA lab - UIUC [[alternative HTML version deleted]]