Claudia Wulff is visiting the Department of Mathematics at Imperial College today (Thursday 29 May) to give a talk in the Dynamical Systems Seminar.  The talk is on “Relative Lyapunov centre bifurcation“.  An abstract follows: relative equilibria and relative periodic orbits (RPOs) are ubiquitous in symmetric Hamiltonian systems. Relative Lyapunov centre bifurcations are bifurcations of relative periodic orbits from relative equilibria corresponding to Lyapunov centre bifurcations of the symmetry reduced dynamics. In this talk a relative Lyapunov centre theorem is proved by combining recent results on persistence of RPOs in Hamiltonian systems with a symmetric Lyapunov centre theorem of Montaldi et al.  Numerical methods are developed for the detection of relative Lyapunov centre bifurcations.  The methods are applied to Lagrangian relative equilibria of the N-body problem.