Perimeter inequality under circular and Steiner symmetrisation: geometric characterisation of extremals
arXiv:2311.17818
Abstract
We study the perimeter inequality under circular symmetrisation, and we provide a full geometric characterisation of equality cases. A careful inspection of the proof shows that a similar characterisation holds true also for the perimeter inequality under Steiner symmetrisation. Our result is based on a new short proof of the perimeter inequality under symmetrisation.
arXiv comment22 pages, 3 figures