  We study stochastic processes that generate non-growing complex networks
without self-loops and multiple edges (simple graphs). The work concentrates on
understanding and formulation of constraints which keep the rewiring stochastic
processes within the class of simple graphs. To formulate these constraints a
new concept of wedge distribution (paths of length 2) is introduced and its
relation to degree-degree correlation is studied. The analysis shows that the
constraints, together with edge selection rules, do not even allow to formulate
a closed master equation in the general case. We also introduce a particular
stochastic process which does not contain edge selection rules, but which, we
believe, can provide some insight into the complexities of simple graphs.
