  In this article we investigate the convergence behavior of gathering
protocols with fixed circulant topologies using tools form dynamical systems.
Given a fixed number of mobile entities moving in the Euclidean plane, we model
a (linear) gathering protocol as a system of (linear) ordinary differential
equations whose equilibria are exactly all possible gathering points. Then, for
a circulant topology we derive a decomposition of the state space into stable
invariant subspaces with different convergence rates by utilizing tools form
dynamical systems theory. It turns out, that decomposition is identical for
every (linear) circulant gathering protocol, whereas only the convergence rates
depend on the weights in interaction graph itself. We end this article with a
brief outlook on robots with limited viewing range.
