English

A dynamical--topological obstruction for smooth isometric embeddings of Riemannian manifolds via incompressible Euler equations

Differential Geometry 2023-09-14 v4 Analysis of PDEs

Abstract

We obtain a dynamical--topological obstruction for the existence of isometric embedding of a Riemannian manifold-with-boundary (M,g)(M,g): if the first real homology of MM is nontrivial, if the centre of the fundamental group is trivial, and if MM is isometrically embedded into a Euclidean space of dimension at least 33, then the isometric embedding must violate a certain dynamical, kinetic energy-related condition (the "rigid isotopy extension property" in Definition 1.1). The arguments are motivated by the incompressible Euler equations with prescribed initial and terminal configurations in hydrodynamics.

Keywords

Cite

@article{arxiv.2006.15423,
  title  = {A dynamical--topological obstruction for smooth isometric embeddings of Riemannian manifolds via incompressible Euler equations},
  author = {Siran Li},
  journal= {arXiv preprint arXiv:2006.15423},
  year   = {2023}
}

Comments

The main Theorem 1.4 of this manuscript is flawed --- in fact, it is vacuously true, for the "rigid isotopy extension property'' can never hold for any isometric embedding. We shall correct this issue in a new preprint entitled "A smooth isotopy of volume-preserving diffeomorphisms on unit cube saving energy through extra dimensions'' (to be uploaded to ArXiv shortly)