Results 11 to 20 of about 872 (123)
Generalized cylinders in semi-Riemannian and spin geometry [PDF]
, 2003 .We use a construction which we call generalized cylinders to give a new proof of the fundamental theorem of hypersurface theory. It has the advantage of being very simple and the result directly extends to semi-Riemannian manifolds and to embeddings ...
Christian Bär +2 more
semanticscholar +1 more source
Every conformal class contains a metric of bounded geometry [PDF]
, 2013 We show that on every manifold, every conformal class of semi-Riemannian metrics contains a metric $$g$$g such that each $$k$$kth-order covariant derivative of the Riemann tensor of $$g$$g has bounded absolute value $$a_k$$ak.
O. Müller, M. Nardmann
semanticscholar +1 more source
Communications on Pure and Applied Mathematics, EarlyView.Abstract Let (Mn,g)$(M^n,g)$ be a complete Riemannian manifold which is not isometric to Rn$\mathbb {R}^n$, has nonnegative Ricci curvature, Euclidean volume growth, and quadratic Riemann curvature decay. We prove that there exists a set G⊂(0,∞)$\mathcal {G}\subset (0,\infty)$ with density 1 at infinity such that for every V∈G$V\in \mathcal {G}$ there ...
Gioacchino Antonelli +2 more
wiley +1 more source
Communications on Pure and Applied Mathematics, EarlyView.Abstract We consider the global dynamics of finite energy solutions to energy‐critical equivariant harmonic map heat flow (HMHF) and radial nonlinear heat equation (NLH). It is known that any finite energy equivariant solutions to (HMHF) decompose into finitely many harmonic maps (bubbles) separated by scales and a body map, as approaching to the ...
Kihyun Kim, Frank Merle
wiley +1 more source
Global and microlocal aspects of Dirac operators: Propagators and Hadamard states
Mathematische Nachrichten, EarlyView.Abstract We propose a geometric approach to construct the Cauchy evolution operator for the Lorentzian Dirac operator on Cauchy‐compact globally hyperbolic 4‐manifolds. We realize the Cauchy evolution operator as the sum of two invariantly defined oscillatory integrals—the positive and negative Dirac propagators—global in space and in time, with ...
Matteo Capoferri, Simone Murro
wiley +1 more source
Mathematical Methods in the Applied Sciences, Volume 48, Issue 6, Page 6912-6917, April 2025.ABSTRACT Nowadays, a substantial portion of investigations concerning the symmetry analysis of differential equations predominantly adhere to a framework comprising the following key procedures: (i) the derivation of symmetries, (ii) the determination of an optimal system, (iii) the utilization of these symmetries to construct invariants or ...
A. Paliathanasis +2 more
wiley +1 more source
Initial State Privacy of Nonlinear Systems on Riemannian Manifolds
International Journal of Robust and Nonlinear Control, EarlyView.ABSTRACT In this paper, we investigate initial state privacy protection for discrete‐time nonlinear closed systems. By capturing Riemannian geometric structures inherent in such privacy challenges, we refine the concept of differential privacy through the introduction of an initial state adjacency set based on Riemannian distances.
Le Liu, Yu Kawano, Antai Xie, Ming Cao
wiley +1 more source
The Geometry of Color in the Light of a Non‐Riemannian Space
Computer Graphics Forum, EarlyView.Abstract We formalize Schrödinger's definitions of hue, saturation, and lightness, building on the foundational idea from Helmholtz that these perceptual attributes can be derived solely from the perceptual metric. We identify three shortcomings in Schrödinger's approach and propose solutions to them.
Roxana Bujack +4 more
wiley +1 more source
Polar Coordinates for the 3/2 Stochastic Volatility Model
Mathematical Finance, Volume 35, Issue 3, Page 708-723, July 2025.ABSTRACT The 3/2 stochastic volatility model is a continuous positive process s with a correlated infinitesimal variance process ν$\nu $. The exact definition is provided in the Introduction immediately below. By inspecting the geometry associated with this model, we discover an explicit smooth map ψ$ \psi $ from (R+)2$({\mathbb{R}}^+)^2 $ to the ...
Paul Nekoranik
wiley +1 more source
Social Rationality and Human Reasoning: Logical Expressivism and the Flat Mind
Topics in Cognitive Science, EarlyView.Abstract This paper attempts to reconcile the claims that the mind is both flat (Chater, 2018) and highly rational (Oaksford & Chater, 2020). According to the flat mind hypothesis, the mind is a mass of inconsistent and contradictory fragments of experience.
Mike Oaksford
wiley +1 more source