2023/07/30 by Jimenez, M. I., Tojeiro, R.
#53B25 #Differential Geometry (math.DG) #FOS: Mathematics
paper · doi:10.48550/arxiv.2307.16341
Li, Ma and Wang have provided in [Deformations of hypersurfaces preserving the Möbius metric and a reduction theorem, Adv. Math. 256 (2014), 156--205] a partial classification of the so-called Moebius deformable hypersurfaces, that is, the umbilic-free Euclidean hypersurfaces f\colon Mn→ ℝn+1 that admit non-trivial deformations preserving the Moebius metric. For n≥ 5, the classification was completed by the authors in \citeJT2. In this article we obtain an infinitesimal version of that classification. Namely, we introduce the notion of an infinitesimal Moebius variation of an umbilic-free immersion f\colon Mn→ ℝm into Euclidean space as a one-parameter family of immersions ft\colon Mn→ ℝm, with t∈ (-ε, ε) and f0=f, such that the Moebius metrics determined by ft coincide up to the first order. Then we characterize isometric immersions f\colon Mn→ ℝm of arbitrary codimension that admit a non-trivial infinitesimal Moebius variation among those that admit a non-trivial conformal infinitesimal variation, and use such characterization to classify the umbilic-free Euclidean hypersurfaces of dimension n≥ 5 that admit non-trivial infinitesimal Moebius variations.