In this paper we consider the evolution of boundaries of sets by a fractional mean curvature flow. We show that for any dimension n >=2, there exist embedded hypersurfaces in R^n which develop a singularity without shrinking to a point. Such examples are well known for the classical mean curvature flow for n >=3. Interestingly, when n = 2, our result provides instead a counterexample in the nonlocal framework to the well-known Grayson’s Theorem, which states that any smooth embedded curve in the plane evolving by (classical) MCF shrinks to a point. The essential step in our construction is an estimate which ensures that a suitably small perturbation of a thin strip has positive fractional curvature at every boundary point.
Neckpinch singularities in fractional mean curvature flows / Cinti, Eleonora; Sinestrari, Carlo; Valdinoci, Enrico. - In: PROCEEDINGS OF THE AMERICAN MATHEMATICAL SOCIETY. - ISSN 0002-9939. - STAMPA. - 146:(2018), pp. 2637-2646. [10.1090/proc/14002]
Neckpinch singularities in fractional mean curvature flows
Cinti, Eleonora;Valdinoci, Enrico
2018
Abstract
In this paper we consider the evolution of boundaries of sets by a fractional mean curvature flow. We show that for any dimension n >=2, there exist embedded hypersurfaces in R^n which develop a singularity without shrinking to a point. Such examples are well known for the classical mean curvature flow for n >=3. Interestingly, when n = 2, our result provides instead a counterexample in the nonlocal framework to the well-known Grayson’s Theorem, which states that any smooth embedded curve in the plane evolving by (classical) MCF shrinks to a point. The essential step in our construction is an estimate which ensures that a suitably small perturbation of a thin strip has positive fractional curvature at every boundary point.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.