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Theodoros Vlachos

Publications and source records attributed to Theodoros Vlachos.

24 records · Page 2Linked to original sources
arXiv2015

The associated family of an elliptic surface and applications to minimal submanifolds

It is well-known that in any codimension a simply connected Euclidean minimal surface has an associated one-parameter family of minimal isometric deformations. In this paper, we show that this is just a special case of the associated family to any simply connected elliptic surface for which all curvature ellipses of a certain order are circles. We also provide the conditions under which this associated family is trivial, extending the known result for minimal surfaces. As an application, we show how the associated family of a minimal Euclidean submanifold of rank two is determined by the associated family of an elliptic surface clarifying the geometry around the associated family of these higher dimensional submanifolds.

math.DG↗
arXiv2014

A class of superconformal surfaces

Superconformal surfaces in Euclidean space are the ones for which the ellipse of curvature at any point is a nondegenerate circle. They can be characterized as the surfaces for which a well-known pointwise inequality relating the intrinsic Gauss curvature with the extrinsic normal and mean curvatures, due to Wintgen (\cite{Wi}) and Guadalupe-Rodríguez (\cite{GR}) for any codimension, reaches equality at all points. In this paper, we show that any pedal surface to a $2$-isotropic Euclidean surface is superconformal. Opposed to almost all known examples, superconformal surfaces in this class are not conformally equivalent to minimal surfaces. Moreover, they can be given in an explicit parametric form since $2$-isotropic surfaces admit a Weierstrass type representation.

math.DG↗
arXiv2014

The dual superconformal surface

It is shown that a superconformal surface with arbitrary codimension in flat Euclidean space has a (necessarily unique) dual superconformal surface if and only if the surface is S-Willmore, the latter a well-known necessary condition to allow a dual as shown by Ma \cite{ma}. Duality means that both surfaces envelope the same central sphere congruence and are conformal with the induced metric. Our main result is that the dual surface to a superconformal surface can easily be described in parametric form in terms of a parametrization of the latter. Moreover, it is shown that the starting surface is conformally equivalent, up to stereographic projection in the nonflat case, to a minimal surface in a space form (hence, S-Willmore) if and only if either the dual degenerates to a point (flat case) or the two surfaces are conformally equivalent (nonflat case).

math.DG↗
arXiv2012

Isometric deformations of minimal surfaces in $S^{4}$

We consider the isometric deformation problem for oriented non simply connected immersed minimal surfaces $f:M \to S^{4}$. We prove that the space of all isometric minimal immersions of $M$ into $S^{4}$ with the same normal curvature function is, within congruences, either finite or a circle. Furthermore, we show that for any compact immersed minimal surface in $S^{4}$ with nontrivial normal bundle there are at most finitely many noncongruent immersed minimal surfaces in $S^{4}$ isometric to it with the same normal curvature function.

math.DG↗
arXiv2006

Hypersurfaces and Codazzi tensors

In this paper we deal with the following problem: Find all Riemannian metrics on a manifold that can be realized isometrically as immersed hypersurfaces in the Euclidean space. We study this problem for a wide class of metrics on hypersurfaces arising from Codazzi tensors.

math.DG↗