Counter-rotational effects on stability of 2+1 -dimensional thin-shell wormholes

The role of angular momentum in a 2+1 -dimensional rotating thin-shell wormhole (TSW) is considered. Particular emphasis is given to stability when the shells (rings) are counter-rotating. We find that counter-rotating halves make the TSW supported by the equation of state of a linear gas more stable. Under a small velocity dependent perturbation, however, it becomes unstable.