“…We refer to [13,14,40,43] for single rotating patches, [26,27] for doubly connected V-states, [42,39] for corotating and counter-rotating vortex pairs and [33] for steady states. See [34] for further properties of rotating solutions and [35,36] for the case of the vortex-sheet problem. See [29,41,58] for related constructions.…”