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We present effective methods to compute equivariant harmonic maps from the universal cover of a surface into a nonpositively curved space. By discretizing the theory appropriately, we show that the energy functional is strongly convex and…

Geometric Topology · Mathematics 2020-01-22 Jonah Gaster , Brice Loustau , Léonard Monsaingeon

We establish two geometric inequalities, respectively, for harmonic functions in exterior Dirichlet problems, and for Green's functions in interior Dirichlet problems, where the boundary surfaces are smooth and convex. Both inequalities…

Differential Geometry · Mathematics 2021-10-11 Yajun Zhou

Numerical experiments with smooth surface extension and image inpainting using harmonic and biharmonic functions are carried out. The boundary data used for constructing biharmonic functions are the values of the Laplacian and normal…

Analysis of PDEs · Mathematics 2018-09-25 S. B. Damelin , N. S. Hoang

We study biharmonic maps between Riemannian manifolds with finite energy and finite bi-energy. We show that if the domain is complete and the target of non-positive curvature, then such a map is harmonic. We then give applications to…

Differential Geometry · Mathematics 2012-10-02 Nobumitsu Nakauchi , Hajime Urakawa , Sigmundur Gudmundsson

For two different scenarios regarding thin elastic structures, described by 2d-F\"oppl-von K\'arm\'an plate models, we obtain energy scaling laws. Firstly, assuming the reference geometry being that of a singular excess-cone, we obtain…

Analysis of PDEs · Mathematics 2022-10-18 Marcel Dengler

Spectral enhancement -- which aims to undo spectral broadening -- leads to integral equations which are ill-posed and require special regularisation techniques for their solution. Even when an optimal regularisation technique is used,…

Numerical Analysis · Mathematics 2009-11-16 Markus Hegland

In this paper we consider approximations introduced by Sacks-Uhlenbeck of the harmonic energy for maps from $S^2$ into $S^2$. We continue the analysis in [6] about limits of $\alpha$-harmonic maps with uniformly bounded energy. Using a…

Differential Geometry · Mathematics 2021-05-19 Tobias Lamm , Andrea Malchiodi , Mario Micallef

A well-known issue of local (adaptive) histogram equalization (LHE) is over-enhancement (i.e., generation of spurious details) in homogenous areas of the image. In this paper, we show that the LHE problem has many solutions due to the…

Computer Vision and Pattern Recognition · Computer Science 2009-09-14 Alireza Avanaki

Magnetic resonance (MR) imaging is commonly used in the clinical setting to non-invasively monitor the body. There exists a large variability in MR imaging due to differences in scanner hardware, software, and protocol design. Ideally, a…

Image and Video Processing · Electrical Eng. & Systems 2024-09-02 Savannah P. Hays , Samuel W. Remedios , Lianrui Zuo , Ellen M. Mowry , Scott D. Newsome , Peter A. Calabresi , Aaron Carass , Blake E. Dewey , Jerry L. Prince

Performance of optimization on quadratic problems sensitively depends on the low-lying part of the spectrum. For large (effectively infinite-dimensional) problems, this part of the spectrum can often be naturally represented or approximated…

Optimization and Control · Mathematics 2024-03-26 Maksim Velikanov , Dmitry Yarotsky

In this paper we classify the low energy $\varepsilon$-harmonic maps from the surfaces of constant curvature with positive genus into the round sphere. We find that all such maps with degree $\pm1$ are all quantitively close to a bubble…

Differential Geometry · Mathematics 2026-04-17 Andrew M. Roberts

Many electronic structure methods rely on the minimization of the energy of the system with respect to the one-body reduced density matrix (1-RDM). To formulate a minimization algorithm, the 1-RDM is often expressed in terms of its…

Chemical Physics · Physics 2025-04-18 Nicolas Cartier , Klaas Giesbertz

We establish a localized Bochner-type rigidity theorem for harmonic maps between Riemannian manifolds. Let $f : (M,g) \to (\overline{M},\overline{g})$ be a harmonic map from a compact manifold. Instead of assuming a global nonpositivity…

Differential Geometry · Mathematics 2026-03-03 Sergey Stepanov

Quantum imaging exploits the spatial correlations between photons to image object features with a higher resolution than a corresponding classical light source could achieve. Using a quantum correlated $N$-photon state, the method of…

In this note, we generalize biharmonic equation for rotationally symmetric maps ([4], [16], [10]) to equivariant maps between model spaces and use it to give a complete classification of rotationally symmetric conformal biharmonic maps from…

Differential Geometry · Mathematics 2019-10-08 Ye-Lin Ou

In this paper, we obtain some new upper bounds for differantiable mappings whose q-th powers are geometrically convex and monotonically decreasing by using the H\"older inequality, Power mean inequality and properties of modulus.

Classical Analysis and ODEs · Mathematics 2013-12-31 M. Emin Özdemir

MRI (Magnetic Resonance Imaging) is a technique used to analyze and diagnose the problem defined by images like cancer or tumor in a brain. Physicians require good contrast images for better treatment purpose as it contains maximum…

Computer Vision and Pattern Recognition · Computer Science 2020-03-17 Sakshi Patel , Bharath K P , Rajesh Kumar Muthu

The presence of off-axis tilt and Petzval curvature, two of the lowest-order off-axis Seidel aberrations, is shown to improve the Fisher information of two-point separation estimation in an incoherent imaging system compared to an…

Optics · Physics 2023-04-12 Kevin Liang

This paper deals with different image theorems, i.e., Love's equivalence principle, the induction equivalence principle and the physical optics equivalence principle, in the spherical geometry. The deviation of image theorem approximation…

Classical Physics · Physics 2020-07-07 Shaolin Liao , Sasan Bakhtiari , Henry Soekmadji

We calculate the radiated energy to $O(\hbar)$ from a charged wave-packet in the uniform magnetic field. In the high-speed and weak-field limit, while the non-commutativity of the system reduces the classical radiation, the additional…

High Energy Physics - Theory · Physics 2015-06-26 Shih-Yuin Lin