ترغب بنشر مسار تعليمي؟ اضغط هنا

Bending and stretching unit vector fields in Euclidean and hyperbolic 3-space

53   0   0.0 ( 0 )
 نشر من قبل Christopher Wood
 تاريخ النشر 2006
  مجال البحث
والبحث باللغة English
 تأليف C. M. Wood




اسأل ChatGPT حول البحث

New examples of harmonic unit vector fields on hyperbolic 3-space are constructed by exploiting the reduction of symmetry arising from the foliation by horospheres. This is compared and contrasted with the analogous construction in Euclidean 3-space, using a foliation by planes, which produces some new examples of harmonic maps from 3-dimensional Euclidean domains to the 2-sphere. Finally, the harmonic unit vector field tangent to a parallel family of hyperbolic geodesics is shown to be unstable, by constructing a class of compactly supported energy-decreasing variations. All examples considered have infinite total bending.



قيم البحث

اقرأ أيضاً

In this paper, we first consider a class of expanding flows of closed, smooth, star-shaped hypersurface in Euclidean space $mathbb{R}^{n+1}$ with speed $u^alpha f^{-beta}$, where $u$ is the support function of the hypersurface, $f$ is a smooth, symme tric, homogenous of degree one, positive function of the principal curvatures of the hypersurface on a convex cone. For $alpha le 0<betale 1-alpha$, we prove that the flow has a unique smooth solution for all time, and converges smoothly after normalization, to a sphere centered at the origin. In particular, the results of Gerhardt cite{GC3} and Urbas cite{UJ2} can be recovered by putting $alpha=0$ and $beta=1$ in our first result. If the initial hypersurface is convex, this is our previous work cite{DL}. If $alpha le 0<beta< 1-alpha$ and the ambient space is hyperbolic space $mathbb{H}^{n+1}$, we prove that the flow $frac{partial X}{partial t}=(u^alpha f^{-beta}-eta u) u$ has a longtime existence and smooth convergence to a coordinate slice. The flow in $mathbb{H}^{n+1}$ is equivalent (up to an isomorphism) to a re-parametrization of the original flow in $mathbb{R}^{n+1}$ case. Finally, we find a family of monotone quantities along the flows in $mathbb{R}^{n+1}$. As applications, we give a new proof of a family of inequalities involving the weighted integral of $k$th elementary symmetric function for $k$-convex, star-shaped hypersurfaces, which is an extension of the quermassintegral inequalities in cite{GL2}.
95 - Keisuke Teramoto 2018
We characterize singularities of focal surfaces of wave fronts in terms of differential geometric properties of the initial wave fronts. Moreover, we study relationships between geometric properties of focal surfaces and geometric invariants of the initial wave fronts.
A Ricci soliton $(M^n,g,v,lambda)$ on a Riemannian manifold $(M^n,g)$ is said to have concurrent potential field if its potential field $v$ is a concurrent vector field. In the first part of this paper we completely classify Ricci solitons with con current potential fields. In the second part we derive a necessary and sufficient condition for a submanifold to be a Ricci soliton in a Riemannian manifold equipped with a concurrent vector field. In the last part, we classify shrinking Ricci solitons with $lambda=1$ on Euclidean hypersurfaces. Several applications of our results are also presented.
We introduce circular evolutes and involutes of framed curves in the Euclidean space. Circular evolutes of framed curves stem from the curvature circles of Bishop directions and singular value sets of normal surfaces of Bishop directions. On the othe r hand, involutes of framed curves are direct generalizations of involutes of regular space curves and frontals in the Euclidean plane. We investigate properties of normal surfaces, circular evolutes, and involutes of framed curves. We can observe that taking circular evolutes and involutes of framed curves are opposite operations under suitable assumptions, similarly to evolutes and involutes of fronts in the Euclidean plane. Furthermore, we investigate the relations among singularities of normal surfaces, circular evolutes, and involutes of framed curves.
62 - Chunhe Li , Yanyan Xu 2016
In the present paper, we revisit the rigidity of hypersurfaces in Euclidean space. We highlight Darboux equation and give new proof of rigidity of hypersurfaces by energy method and maximal principle.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا