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1992, Communications in Mathematical Physics
In this paper, we studied the regularity problem for harmonic maps into hyperbolic spaces with prescribed singularities along codimension two submanifolds. This is motivated from one of Hawking's conjectures on the uniqueness of Kerr solutions among all axially symmetric asymptotically flat stationary solutions to the vacuum Einstein equation in general relativity.
American Journal of Mathematics, 1996
The Einstein/Abelian-Yang-Mills Equations reduce in the stationary and axially symmetric case to a harmonic map with prescribed singularities ϕ : R 3 \Σ → H k+1 C into the (k +1)-dimensional complex hyperbolic space. In this paper, we prove the existence and uniqueness of harmonic maps with prescribed singularities ϕ : R n \ Σ → H, where Σ is an unbounded smooth closed submanifold of R n of codimension at least 2, and H is a real, complex, or quaternionic hyperbolic space. As a corollary, we prove the existence of solutions to the reduced stationary and axially symmetric Einstein/Abelian-Yang-Mills Equations.
Communications in Analysis and Geometry, 2010
We discuss regularity questions for harmonic maps from a n-dimensional Riemannian polyhedral complex X to a non-positively curved metric space. The main theorems assert, assuming Lipschitz regularity of the metric on the domain complex, that such maps are locally Hölder continuous with explicit bounds of the Hölder constant and exponent on the energy of the map and the geometry of the domain and locally Lipschitz continuous away from the (n − 2)-skeleton of the complex. Moreover, if x is a point on the k-skeleton (k ≤ n − 2) we give explicit dependence of the Hölder exponent at a point near x on the combinatorial and geometric information of the link of x in X and the link of the k-dimensional skeleton in X at x.
Journal of Geometric Analysis, 1996
Here we obtain everywhere regularity of weak solutions of some nonlinear elliptic systems with borderline growth, including n-harmonic maps between manifolds or map with constant volumes. Other results in this paper include regularity up to the boundary and a removability theorem for isolated singularities. § 1. Introduction Let n, m ≥ 2 be integers, p ∈ (1, n] and Ω be a smooth bounded domain Ω ⊂ R n. As usual, W 1,p (Ω, R m) is the set of all functions u ∈ L p (Ω, R m) with finite p-energy Ω |∇u| p < ∞; it is a Banach space with the norm u W 1,p = Ω |u| p + |∇u| p .
International Journal of Pure and Applied Mathematics
This paper deals with a new class of harmonic maps and morphisms into globally null manifolds which admit a global null vector field and a complete Riemannian hypersurface. We concentrate on the fundamental existence problem of harmonic maps and morphisms for this new class and establish an interplay between harmonic maps, morphisms, globally null manifolds and globally hyperbolic spacetimes of general relativity.
Bulletin of the American Mathematical Society, 1992
Shoen and Uhlenbeck showed that "tangent maps" can be defined at singular points of energy minimizing maps. Unfortunately these are not unique, even for generic boundary conditions. Examples are discussed which have isolated singularities with a continuum of distinct tangent maps.
Glasgow Mathematical Journal, 2008
We consider transversally harmonic foliated maps between two Riemannian manifolds equipped with Riemannian foliations. We give various characterisations of such maps and we study the relation between the properties ‘harmonic’ and ‘transversally harmonic’ for a given map. We also consider these problems for particular classes of manifolds: manifolds with transversally almost Hermitian foliations and Riemannian flows.
1995
The harmonicity condition of the curvature 2-form of a pseudo- Riemannian manifold is formulated on the basis of annulment of this form by the de Rham-Lichnerowicz Laplacian. The following theorem is proved: The curvature 2-form of any Einstein manifold is harmonic.
2019
In this paper, we study harmonic map, pluriharmonicity and harmonic morphisms on trans-S-manifolds. Different results are discussed for different cases of trans-S-manifolds as trans-S-manifolds are the genralization of C-manifolds, f -Kenmotsu and S-manifolds. M.S.C. 2010: 53C55, 53C43, 58E20.
arXiv (Cornell University), 2018
Let {u n } be a sequence of maps from a compact Riemann surface M with smooth boundary to a general compact Riemannian manifold N with free boundary on a smooth submanifold K ⊂ N satisfying sup n ∇u n L 2 (M) + τ(u n) L 2 (M) ≤ Λ, where τ(u n) is the tension field of the map u n. We show that the energy identity and the no neck property hold during a blow-up process. The assumptions are such that this result also applies to the harmonic map heat flow with free boundary, to prove the energy identity at finite singular time as well as at infinity time. Also, the no neck property holds at infinity time. 1. introduction Let (M, g) be a compact Riemannian manifold with smooth boundary and (N, h) be a compact Riemannian manifold of dimension n. Let K ⊂ N be a k−dimensional closed submanifold where 1 ≤ k ≤ n. For a mapping u ∈ C 2 (M, N), the energy density of u is defined by e(u) = 1 2 |∇u| 2 = Trace g u * h, where u * h is the pull-back of the metric tensor h. The energy of the mapping u is defined as E(u) = M e(u)dvol g. Define C(K) = u ∈ C 2 (M, N); u(∂M) ⊂ K. A critical point of the energy E over C(K) is a harmonic map with free boundary u(∂M) on K. The problem of the existence, uniqueness and regularity of such harmonic maps with a free boundary was first systematically investigated in [8]. By Nash's embedding theorem, (N, h) can be isometrically embedded into some Euclidean space R N. Then we can get the Euler-Lagrange equation ∆ g u = A(u)(∇u, ∇u),
Commentarii Mathematici Helvetici, 1995
In this paper we give a method for constructing complete minimal submanifolds of the hyperbolic spaces H '~. They are regular fibres of harmonic morphisms from H m with values in Riemann surfaces.
Acta Mathematica, 1977
Manuscripta Mathematica, 1988
2020
In this paper, we study the existence of f -harmonic maps into Riemannian manifolds admitting a homothetic vector fields. Also we present some properties for the f -biharmonicity of submanifolds of Rn, where f is a smooth positive function on Rn. 1. Preliminaries and Notations Let (M, g) be a Riemannian manifold. By R , we denote the Riemannian curvature tensor of (M, g). Then R is defined by (1) R (X,Y )Z = ∇X∇Y Z −∇Y ∇X Z −∇[X,Y ]Z, where ∇ is the Levi-Civita connection with respect to g, and X,Y, Z ∈ Γ(TM). The divergence of (0, p)-tensor α on M is defined by (2) (div α)(X1, . . . , Xp−1) = (∇Mei α)(ei, X1, . . . , Xp−1), where X1, . . . , Xp−1 ∈ Γ(TM) and {ei} is an orthonormal frame. Given a smooth function λ on M , the gradient of λ is defined by (3) g(grad λ,X) = X(λ), the Hessian of λ is defined by (4) (Hess λ)(X,Y ) = g(∇X gradλ, Y ), where X,Y ∈ Γ(TM) (for more details, see, for example, [9]). Let φ : (M, g)→ (N,h) be a smooth map between two Riemannian manifolds, τ(φ) the...
Annales de la faculté des sciences de Toulouse Mathématiques, 2004
Mathématiques FRÉDÉRIC HÉLEIN Removability of singularities of harmonic maps into pseudo-Riemannian manifolds Tome XIII, n o 1 (2004), p. 45-71. <http://afst.cedram.org/item?id=AFST_2004_6_13_1_45_0> © Annales de la faculté des sciences de Toulouse Mathématiques, 2004, tous droits réservés. L'accès aux articles de la revue « Annales de la faculté des sciences de Toulouse, Mathématiques » (http://afst.cedram.org/), implique l'accord avec les conditions générales d'utilisation (http://afst.cedram. org/legal/). Toute reproduction en tout ou partie cet article sous quelque forme que ce soit pour tout usage autre que l'utilisation à fin strictement personnelle du copiste est constitutive d'une infraction pénale. Toute copie ou impression de ce fichier doit contenir la présente mention de copyright. cedram Article mis en ligne dans le cadre du Centre de diffusion des revues académiques de mathématiques http://www.cedram.org/
arXiv: Differential Geometry, 2020
In this paper, we study the existence of harmonic and bi-harmonic maps into Riemannian manifolds admitting a conformal vector field, or a nontrivial Ricci solitons.
The Annals of Mathematics, 1999
For stationary harmonic maps between Riemannian manifolds, we provide a necessary and sufficient condition for the uniform interior and boundary gradient estimates in terms of the total energy of maps. We also show that if analytic target manifolds do not carry any harmonic S 2 , then the singular sets of stationary maps are m ≤ n − 4 rectifiable. Both of these results follow from a general analysis on the defect measures and energy concentration sets associated with a weakly converging sequence of stationary harmonic maps.
In this note, we extend the definition of harmonic and biharmonic maps between two Riemannian manifolds, and we present some properties for f -harmonic maps and f -biharmonic maps.
Contemporary Mathematics, 2005
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