Consider the following model to grow simple networks. At time t $=1$ we start with a

complete network with n$0=6$ nodes. At each time step t $>1$ a new node is added to

the network. The node arrives together with m $=2$ new links, which are connected to

m $=2$ different nodes already present in the network. The probability $\backslash$Pi i that a new

link is connected to node i is:

$\backslash$Pi i $=$

ki $1$

Z

with Z $=$

N

X

$($t$1)$

j$=1$

$($kj $1)$

where ki

is the degree of node i$,$