scholarly journals On naturality of some construction of connections

2020 ◽  
Vol 74 (1) ◽  
pp. 57
Author(s):  
Jan Kurek ◽  
Włodzimierz Mikulski
Keyword(s):  
Linear Connection ◽  
Bundle Functor ◽  
Fibred Manifold ◽  
Natural Transformations ◽  
General Connection

Let \(F\) be a bundle functor on the category of all fibred manifolds and fibred maps. Let \(\Gamma\) be a general connection in a fibred manifold \(\mathrm{pr}:Y\to M\) and \(\nabla\) be a classical linear connection on \(M\). We prove that the  well-known general connection \(\mathcal{F}(\Gamma,\nabla)\) in \(FY\to M\) is canonical with respect to fibred maps and with respect to natural transformations of bundle functors.

scholarly journals The induced connections on total spaces of fibred manifolds

2015 ◽  
Vol 97 (111) ◽  
pp. 149-160
Author(s):  
Włodzimierz Mikulski
Keyword(s):  
Linear Connection ◽  
Linear Connections ◽  
Fibred Manifold ◽  
Torsion Free ◽  
General Connection

Let Y ? M be a fibred manifold with m-dimensional base and n-dimensional fibres. If m ? 2 and n ? 3, we classify all linear connections A(?, ?, ?) : TY ? J1(TY ? Y) in TY ? Y (i.e., classical linear connections on Y) depending canonically on a system (?, ?, ?) consisting of a general connection ? : Y ? J1Y in Y ? M, a torsion free classical linear connection ? : TM ? J1(TM ? M) on M and a linear connection ? : V Y ? J1(VY ? Y ) in the vertical bundle VY ? Y.

INDUCED CONNECTIONS ON TOTAL SPACES OF FIBER BUNDLES

2010 ◽  
Vol 07 (04) ◽  
pp. 705-711 ◽  
Author(s):  
IVAN KOLÁŘ
Keyword(s):  
Linear Connection ◽  
Total Space ◽  
Fiber Bundles ◽  
Natural Operators ◽  
General Connection

We present a construction transforming a general connection Γ on a fibered manifold Y → M and a classical connection Λ on its base M into a classical connection on the total space Y by means of a vertical parallelism Φ and an auxiliary linear connection Δ. The relations to the theory of gauge-natural operators are discussed.

scholarly journals On canonical constructions on connections

2016 ◽  
Vol 70 (1) ◽  
pp. 27
Author(s):  
Jan Kurek ◽  
Włodzimierz Mikulski
Keyword(s):  
Fibred Manifold ◽  
General Connection

We study  how a projectable general connection \(\Gamma\) in a 2-fibred manifold \(Y^2\to Y^1\to Y^0\)  and a general vertical connection \(\Theta\) in \(Y^2\to Y^1\to Y^0\) induce a general connection \(A(\Gamma,\Theta)\) in \(Y^2\to Y^1\).

scholarly journals Gauging the higher-spin-like symmetries by the Moyal product

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
M. Cvitan ◽  
P. Dominis Prester ◽  
S. Giaccari ◽  
M. Paulišić ◽  
I. Vuković
Keyword(s):  
Linear Connection ◽  
Covariant Formulation ◽  
Formal Similarity ◽  
Commutative Field ◽  
Gauge Transformations ◽  
Yang Mills ◽  
Higher Derivative ◽  
Novel Approach ◽  
Emergent Geometry ◽  
Higher Spin

Abstract We analyze a novel approach to gauging rigid higher derivative (higher spin) symmetries of free relativistic actions defined on flat spacetime, building on the formalism originally developed by Bonora et al. and Bekaert et al. in their studies of linear coupling of matter fields to an infinite tower of higher spin fields. The off-shell definition is based on fields defined on a 2d-dimensional master space equipped with a symplectic structure, where the infinite dimensional Lie algebra of gauge transformations is given by the Moyal commutator. Using this algebra we construct well-defined weakly non-local actions, both in the gauge and the matter sector, by mimicking the Yang-Mills procedure. The theory allows for a description in terms of an infinite tower of higher spin spacetime fields only on-shell. Interestingly, Euclidean theory allows for such a description also off-shell. Owing to its formal similarity to non-commutative field theories, the formalism allows for the introduction of a covariant potential which plays the role of the generalised vielbein. This covariant formulation uncovers the existence of other phases and shows that the theory can be written in a matrix model form. The symmetries of the theory are analyzed and conserved currents are explicitly constructed. By studying the spin-2 sector we show that the emergent geometry is closely related to teleparallel geometry, in the sense that the induced linear connection is opposite to Weitzenböck’s.

Orientation relationships of carlsbergite in schreibersite and kamacite in the north Chile iron meteorite

2006 ◽  
Vol 70 (4) ◽  
pp. 373-382 ◽  
Author(s):  
G. Nolze ◽  
G. Wagner ◽  
R. Saliwan Neumann ◽  
R. Skála ◽  
V. Geist
Keyword(s):  
Electron Backscatter Diffraction ◽  
Metallic Matrix ◽  
Iron Meteorite ◽  
Orientation Relationships ◽  
Orientation Relation ◽  
Crystalline Materials ◽  
The North ◽  
Transmission Electron ◽  
Backscatter Diffraction ◽  
General Connection

AbstractThe crystallographic orientation of carlsbergite (CrN) in the north Chile meteorite (hexahedrite) was investigated using electron backscatter diffraction and transmission electron microscopy. These studies examined the CrN crystals in the rhabdites (idiomorphic schreibersite) and in kamacite. It was found that the CrN crystals embedded in rhabdite show a number of different orientation relationships with the host crystals. These orientations can be explained based on the lattice dimensions of both coexisting crystalline materials. It was also found that both carlsbergite and kamacite are characterized by a high dislocation density (≥ l09 cm-2) while rhabdite is free of dislocations. It is supposed that in spite of the deformed metallic matrix, a general connection between the orientation relation of all the phases involved exists.

Embeddings of Butterflies into Hypermeshes

1998 ◽  
Vol 08 (03) ◽  
pp. 337-350
Author(s):  
Sook-Yeon Kim ◽  
Oh-Heum Kwon ◽  
Kyung-Yong Chwa
Keyword(s):  
Aspect Ratio ◽  
Interconnection Network ◽  
Linear Connection ◽  
Parallel Computers ◽  
Multiple Copies

Hypermeshes have been given much attention as a versatile interconnection network of parallel computers. A hypermesh is obtained from a mesh by replacing each linear connection with a hyperedge. In this paper, we show how to embed a butterfly or multiple copies of a butterfly into a hypermesh. First, a butterfly B(s) of (s + 1)2s nodes is embedded into a 2s × X hypermesh where X = 2⌊ log 2 s ⌋+ 1. Second, the butterfly B(s) is embedded into a square hypermesh. Third, multiple copies of the butterfly B(s) are embedded into a hypermesh of variable aspect ratio. The efficiency of these embeddings is measured by alignment cost, congestion, and expansion. The alignment cost of all of these embeddings is optimal. The congestion of the first and third embedding is optimal. The expansion of the first and third embedding is one if s = 2k - 1 for some integer k, otherwise, less than two. The expansion of the second embedding is 2 + ∊ (s) where ∊(s) = (2 log (s + 1) + 2)/(s + 1).

scholarly journals Effectiveness Testing of an Inverse Method for Balancing Nonlinear Rotordynamic Systems

2018 ◽  
Author(s):  
Sergio G. Torres Cedillo ◽  
Philip Bonello ◽  
Ghaith Ghanim Al-Ghazal ◽  
Jacinto Cortés Pérez ◽  
Alberto Reyes Solis
Keyword(s):  
Inverse Problem ◽  
Inverse Method ◽  
Linear Connection ◽  
The Other ◽  
Squeeze Film ◽  
Squeeze Film Damper ◽  
Operational Conditions ◽  
Non Invasive ◽  
Highly Nonlinear ◽  
Aero Engine

Modern aero-engine structures typically have at least two nested rotors mounted within a flexible casing via squeeze-film damper (SFD) bearings. The inaccessibility of the HP rotor under operational conditions motivates the use of a non-invasive inverse problem procedure for identifying the unbalance. Such an inverse problem requires prior knowledge of the structure and measurements of the vibrations at the casing. Recent work by the authors reported a non-invasive inverse method for the balancing of rotordynamic systems with nonlinear squeeze-film damper (SFD) bearings, which overcomes several limitations of earlier works. However, it was not applied to a common practical configuration wherein the HP rotor is mounted on the casing via just one weak linear connection (retainer spring), with the other connections being highly nonlinear SFDs. The analysis of the present paper considers such a system. It explores the influence of the condition number and how it is affected as the number of sensors and/or measurement speeds is increased. The results show that increasing the number of measurement speeds has a far more significant impact on the conditioning of the problem than increasing the number of sensors. The balancing effectiveness is reasonably good under practical noise level conditions, but significantly lower than obtained for the previously considered simpler configurations.

Vertical Chern Type Classes on Complex Finsler Bundles

2011 ◽  
Vol 57 (2) ◽  
pp. 377-386
Author(s):  
Cristian Ida
Keyword(s):  
Differential Forms ◽  
Linear Connection ◽  
Curvature Form ◽  
Cohomology Groups ◽  
Finsler Manifolds ◽  
Invariance Properties ◽  
Type Classes

Vertical Chern Type Classes on Complex Finsler BundlesIn the present paper, we define vertical Chern type classes on complex Finsler bundles, as an extension of thev-cohomology groups theory on complex Finsler manifolds. These classes are introduced in a classical way by using closed differential forms with respect to the conjugated vertical differential in terms of the vertical curvature form of Chern-Finsler linear connection. Also, some invariance properties of these classes are studied.

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