Distributional geometry

1979 ◽  
Vol 20 (7) ◽  
pp. 1423-1426 ◽  
Author(s):  
Phillip E. Parker
Keyword(s):  
Distributional Geometry

Singular general relativity using the Colombeau approach. I. Distributional Schwarzschild geometry from nonsmooth regularization via horizon

2020 ◽  
Vol 33 (2) ◽  
pp. 180-199
Author(s):  
Jaykov Foukzon ◽  
Elena R. Men’kova ◽  
Alexander A. Potapov
Keyword(s):  
General Relativity ◽  
Schwarzschild Solution ◽  
Schwarzschild Geometry ◽  
Distributional Geometry ◽  
Nonsmooth Regularization

We studied the Schwarzschild solution using Colombeau distributional geometry [M. Kunzinger and R. Steinbauer, Trans. Am. Math. Soc. 354, 4179 (2002)], thus without leaving Schwarzschild coordinates.

The point free Colombeau geometry in singular general relativity

2021 ◽  
Author(s):  
Ja. Foukzon ◽  
A.A. Potapov ◽  
E.R. Men'kova
Keyword(s):  
General Relativity ◽  
Physical Interpretation ◽  
Curvature Scalar ◽  
Schwarzschild Spacetime ◽  
Problem Statement ◽  
Colombeau Algebra ◽  
Schwarzschild Solution ◽  
Metric Tensor ◽  
Levi Civita Connection ◽  
Distributional Geometry

The problem statement. We argue that the canonical interpretation of the Schwarzschild spacetime in contemporary general relativity is wrong and that revision is needed. And we argue that the Schwarzschild solution is impossible to treat classically, since the Levi-Cività connection is not available for the whole Schwarzschild spacetime (Sch,gijSch (t r, , ,θϕ)) ; where Sch=×(({r ≥ 2m} {∪ ≤ ≤0 r 2m})×S2) ; but it can only be treated by using an embedding of the classical Schwarzschild metric tensor gijSch; ,i j =1,2,3,4 into Colombeau algebra δ(4,Σ),Σ= ={r 2m} {∪ =r 0} supergeneralized functions. The classical Schwarzschild spacetime could be extended up to the distributional semi-Riemannian manifold endowed on the tangent bundle with the Colombeau distributional metric tensor. The aim. The development of new physical interpretation for the distributional curvature scalar (Rε( )r )ε and square scalar (Rεμν( )r Rμνε, ( )r )ε, (Rερσμν( )r Rρδμνε, ( )r )εis aimed. Results. The Schwarzschild solution using Colombeau distributional geometry without leaving Schwarzschild coordinates (t r, , ,θϕ) is studied. We obtain that the distributional Ricci tensor and the curvature scalar are δ-type, (R rε( ))ε=−m rδ( − 2m) ,>0 . The practical value. As distributional square scalars are essentially nonclassical Colombeau type distributions: (Rεμν( )r Rμνε, ( )r )ε, (Rερσμν( )r Rρσμνε, ( )r )ε∈(3 )\ ′(3 ), this provides a new physical interpretation for the distributional curvature scalar (R rε( ))ε and square scalars (Rεμν( )r Rμνε, ( )r )ε, (Rερσμν( )r Rρδμνε, ( )r )ε.

scholarly journals Color-complexity enabled exhaustive color-dots identification and spatial patterns testing in images

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0251258
Author(s):  
Shuting Liao ◽  
Li-Yu Liu ◽  
Ting-An Chen ◽  
Kuang-Yu Chen ◽  
Fushing Hsieh
Keyword(s):  
Spanning Trees ◽  
Identification Algorithm ◽  
Value Evaluation ◽  
Lighting Conditions ◽  
Color System ◽  
Aerial Vehicle ◽  
Color Identification ◽  
Color Pixel ◽  
Distributional Geometry ◽  
Clustering Tree

Our computational developments and analyses on experimental images are designed to evaluate the effectiveness of chemical spraying via unmanned aerial vehicle (UAV). Our evaluations are in accord with the two perspectives of color-complexity: color variety within a color system and color distributional geometry on an image. First, by working within RGB and HSV color systems, we develop a new color-identification algorithm relying on highly associative relations among three color-coordinates to lead us to exhaustively identify all targeted color-pixels. A color-dot is then identified as one isolated network of connected color-pixel. All identified color-dots vary in shapes and sizes within each image. Such a pixel-based computing algorithm is shown robustly and efficiently accommodating heterogeneity due to shaded regions and lighting conditions. Secondly, all color-dots with varying sizes are categorized into three categories. Since the number of small color-dot is rather large, we spatially divide the entire image into a 2D lattice of rectangular. As such, each rectangle becomes a collective of color-dots of various sizes and is classified with respect to its color-dots intensity. We progressively construct a series of minimum spanning trees (MST) as multiscale 2D distributional spatial geometries in a decreasing-intensity fashion. We extract the distributions of distances among connected rectangle-nodes in the observed MST and simulated MSTs generated under the spatial uniformness assumption. We devise a new algorithm for testing 2D spatial uniformness based on a Hierarchical clustering tree upon all involving MSTs. This new tree-based p-value evaluation has the capacity to become exact.

scholarly journals A nonlinear theory of distributional geometry

2020 ◽  
Vol 476 (2244) ◽  
pp. 20200642 ◽  
Author(s):  
E. A. Nigsch ◽  
J. A. Vickers
Keyword(s):  
Differential Geometry ◽  
Nonlinear Theory ◽  
Delta Function ◽  
Generalized Functions ◽  
Lie Derivative ◽  
Tensor Fields ◽  
Generalized Metric ◽  
Nonlinear Generalized Functions ◽  
Distributional Geometry ◽  
Conical Metric

This paper builds on the theory of nonlinear generalized functions begun in Nigsch & Vickers (Nigsch, Vickers 2021 Proc. R. Soc. A 20200640 ( doi:10.1098/rspa.2020.0640 )) and extends this to a diffeomorphism-invariant nonlinear theory of generalized tensor fields with the sheaf property. The generalized Lie derivative is introduced and shown to commute with the embedding of distributional tensor fields and the generalized covariant derivative commutes with the embedding at the level of association. The concept of a generalized metric is introduced and used to develop a non-smooth theory of differential geometry. It is shown that the embedding of a continuous metric results in a generalized metric with well-defined connection and curvature and that for C 2 metrics the embedding preserves the curvature at the level of association. Finally, we consider an example of a conical metric outside the Geroch–Traschen class and show that the curvature is associated to a delta function.

scholarly journals Distributional geometry of squashed cones

2013 ◽  
Vol 88 (4) ◽  
Author(s):  
Dmitri V. Fursaev ◽  
Alexander Patrushev ◽  
Sergey N. Solodukhin
Keyword(s):  
Distributional Geometry

scholarly journals Nonlinear generalized functions on manifolds

2020 ◽  
Vol 476 (2244) ◽  
pp. 20200640
Author(s):  
E. A. Nigsch ◽  
J. A. Vickers
Keyword(s):  
Covariant Derivative ◽  
Scalar Fields ◽  
Generalized Functions ◽  
Lie Derivative ◽  
Subsequent Paper ◽  
Schwartz Distributions ◽  
Colombeau Algebras ◽  
Algebras Of Generalized Functions ◽  
Tensor Distributions ◽  
Distributional Geometry

In this work, we adopt a new approach to the construction of a global theory of algebras of generalized functions on manifolds based on the concept of smoothing operators. This produces a generalization of previous theories in a form which is suitable for applications to differential geometry. The generalized Lie derivative is introduced and shown to extend the Lie derivative of Schwartz distributions. A new feature of this theory is the ability to define a covariant derivative of generalized scalar fields which extends the covariant derivative of distributions at the level of association. We end by sketching some applications of the theory. This work also lays the foundations for a nonlinear theory of distributional geometry that is developed in a subsequent paper that is based on Colombeau algebras of tensor distributions on manifolds.

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