arXiv subjects

Xiang Ma

Publications and source records attributed to Xiang Ma.

128 records · Page 8Linked to original sources

arXiv2005

Adjoint Transform of Willmore Surfaces in $n$-sphere

After the surface theory of Möbius geometry, this study concerns a pair of conformally immersed surfaces in $n$-sphere. Two new invariants $θ$ and $ρ$ associated with them are introduced as well as the notion of touch and co-touch. This approach is helpful in research about transforms of certain surface classes. As an application, we define adjoint transform for any given Willmore surface in $n$-sphere. It always exists locally (yet not unique in general) and generalizes known duality theorems of Willmore surfaces. This theory on surface pairs reaches its high point by a characterization of adjoint Willmore surfaces in terms of harmonic maps.

math.DG↗

arXiv2004

Isothermic and S-Willmore Surfaces as Solutions to Blaschke's Problem

We consider the generalization of classical Blaschke's Problem to higher codimension case, characterizing Darboux pair of isothermic surfaces and dual S-Willmore surfaces as the only non-trivial surface pairs that envelop a 2-sphere congruence and conformally correspond to each other. When the sphere congruence is the mean curvature spheres of one envelop surface, it must be a cmc-1 surface in hyperbolic 3-space, or a S-Willmore surface. A study of conformally immersed surface pairs is indicated with discussion on the geometric meaning of new invariants.

math.DG↗