scholarly journals Characterization of a Banach-Finsler manifold in terms of the algebras of smooth functions

2013 ◽  
Vol 142 (3) ◽  
pp. 1075-1087 ◽  
Author(s):  
J. A. Jaramillo ◽  
M. Jiménez-Sevilla ◽  
L. Sánchez-González
Author(s):  
Ahmed Abouelaz

AbstractWe define and study the d-plane Radon transform, namely R, on the n-dimensional (flat) torus. The transformation R is obtained by integrating a suitable function f over all d-dimensional geodesics (d-planes in the torus). We specially establish an explicit inversion formula of R and we give a characterization of the image, under the d-plane Radon transform, of the space of smooth functions on the torus.


2018 ◽  
Vol 61 (3) ◽  
pp. 628-636 ◽  
Author(s):  
Marijan Marković

AbstractIn this paper we give some generalizations and improvements of the Pavlović result on the Holland–Walsh type characterization of the Bloch space of continuously differentiable (smooth) functions in the unit ball in Rm.


2013 ◽  
Vol 265 (9) ◽  
pp. 1870-1915 ◽  
Author(s):  
Lizaveta Ihnatsyeva ◽  
Antti V. Vähäkangas

Author(s):  
HIROSHI HASEGAWA

We develop a non-parametric information geometry on finite-dimensional matrix manifolds by using the Fréchet differentiation. Taking the simplest prototype Riemannian metric form [Formula: see text], [Formula: see text] with the Fréchet derivative D on a pair of smooth functions g(ρ) and g*(ρ) of the density matrix ρ, we prove the WYD identification theorem: this metric is identified with the normalized Wigner–Yanase–Dyson skew information (the WYD metric), if and only if the metric form satisfies the monotonicity under every stochastic mapping T on ρ and A: [Formula: see text]. On this basis, we establish (a) a fine structure of the partial order in the set ℱ of all monotone metrics such that ℱ power ∪ℱ WYD forms a linearly ordered subset of ℱ with the same mini-max bound, where ℱ power (the power-mean metrics) interpolates the Bures and the WYD metrics (b) a characterization of the quasi-entropy S (ρ, σ)= Tr F (Δσ, ρ)ρ induced by the metric-characterizing function f WYD (x) of the WYD metric (c) an affine connection on the above metric which is torsionless to guarantee the quantum version of the ±α-connection, provided α∈[-3, 3].


2009 ◽  
Vol 51 (2) ◽  
pp. 301-314 ◽  
Author(s):  
S. M. BUCKLEY ◽  
K. FALK ◽  
D. J. WRAITH

AbstractWe consider Ptolemy's inequality in a metric space setting. It is not hard to see that CAT(0) spaces satisfy this inequality. Although the converse is not true in full generality, we show that if our Ptolemaic space is either a Riemannian or Finsler manifold, then it must also be CAT(0). Ptolemy's inequality is closely related to inversions of metric spaces. We exploit this link to establish a new characterization of Euclidean space amongst all Riemannian manifolds.


Author(s):  
Sharief Deshmukh ◽  
Ibrahim Al-Dayel

There are two smooth functions [Formula: see text] and [Formula: see text] associated to a nontrivial concircular vector field [Formula: see text] on a connected Riemannian manifold [Formula: see text], called potential function and connecting function. In this paper, we show that presence of a timelike nontrivial concircular vector field influences the geometry of generalized Robertson–Walker space-times. We use a timelike concircular vector field [Formula: see text] on an [Formula: see text] -dimensional connected conformally flat Lorentzian manifold, [Formula: see text], to find a characterization of generalized Robertson–Walker space-time with  fibers Einstein manifolds. It is interesting to note that for [Formula: see text] the concircular vector field annihilates energy-momentum tensor and also that in this case the potential function [Formula: see text] is harmonic. In the second part of this paper, we show that presence of a nontrivial concircular vector field [Formula: see text] with connecting function [Formula: see text] on a complete and connected [Formula: see text] -dimensional conformally flat Riemannian manifold [Formula: see text], [Formula: see text], with Ricci curvature [Formula: see text] non-negative, satisfying [Formula: see text], is necessary and sufficient for [Formula: see text] to be isometric to either a sphere [Formula: see text] or to the Euclidean space [Formula: see text], where [Formula: see text] is the scalar curvature.


2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
M. I. Garrido ◽  
J. A. Jaramillo ◽  
Y. C. Rangel

We study the smooth approximation of Lipschitz functions on Finsler manifolds, keeping control on the corresponding Lipschitz constants. We prove that, given a Lipschitz functionf:M→ℝdefined on a connected, second countable Finsler manifoldM, for each positive continuous functionε:M→(0,∞)and eachr>0, there exists aC1-smooth Lipschitz functiong:M→ℝsuch that|f(x)-g(x)|≤ε(x), for everyx∈M, andLip(g)≤Lip(f)+r. As a consequence, we derive a completeness criterium in the class of what we call quasi-reversible Finsler manifolds. Finally, considering the normed algebraCb1(M)of allC1functions with bounded derivative on a complete quasi-reversible Finsler manifoldM, we obtain a characterization of algebra isomorphismsT:Cb1(N)→Cb1(M)as composition operators. From this we obtain a variant of Myers-Nakai Theorem in the context of complete reversible Finsler manifolds.


2010 ◽  
Vol 3 (4) ◽  
pp. 2833-2859 ◽  
Author(s):  
C. K. Liang ◽  
A. Eldering ◽  
F. W. Irion ◽  
W. G. Read ◽  
E. J. Fetzer ◽  
...  

Abstract. In this paper, we analyze averaging kernels to assess the sensitivity of the Aqua Atmospheric Infrared Sounder (AIRS) and Aura Microwave Limb Sounder (MLS) to water vapor. The averaging kernels, in the tropical and extra-tropical upper tropospheric and lower stratospheric region of the atmosphere, indicate that AIRS is primarily sensitive to water vapor concentrations typical of tropospheric values up to a level around 260 hPa. At lower pressures AIRS retrievals lose sensitivity to water vapor, though not completely as indicated by the non-zero verticalities at pressures less than 260 hPa. The MLS is able to provide high quality retrievals, with verticalities ~1 for all pressure levels, down to the same level for where AIRS begins to lose sensitivity. Previous analyses have estimated both instruments to have overlapping sensitivity to water vapor over a half temperature scale height layer, within the upper troposphere, for concentrations between ~30–400 ppmv. Thus, we implement a method using the averaging kernel information to join the AIRS and MLS profiles into an merged set of water vapor profiles. The final combined profiles are not only smooth functions with height but preserve the atmospheric state as interpreted by both the AIRS and MLS instruments.


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