Associated Derived Invariants Of Geometric Mappings
Nenad O. Vesi\'c

TL;DR
This paper derives general invariants for geometric mappings in symmetric affine connection spaces, extending previous invariants and relating them to the Thomas projective parameter and Weyl tensor.
Contribution
It introduces new general invariants for geometric mappings, expanding the theoretical framework beyond existing basic invariants.
Findings
Derived new invariants related to geometric mappings
Connected invariants with Thomas projective parameter
Linked invariants to Weyl projective tensor
Abstract
General invariants of a geometric mapping of a symmetric affine connection space are obtained in this paper. These invariants are generalizations of the previous obtained basic invariants (see [16]). Moreover, these invariants are related with the Thomas projective parameter and the Weyl projective tensor.
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Taxonomy
TopicsAdvanced Differential Geometry Research · Geometric Analysis and Curvature Flows · Mathematics and Applications
ASSOCIATED DERIVED INVARIANTS
of Geometric Mappings
Nenad O. Vesić111Faculty of Science and Mathematics, Niš, Serbia, Serbian Ministry of Education, Science and Technological Development, Grant No. 174012
Abstract
General invariants of a geometric mapping of a symmetric affine connection space are obtained in this paper. These invariants are generalizations of the previous obtained basic invariants (see [16]). Moreover, these invariants are related with the Thomas projective parameter and the Weyl projective tensor.
Key words: invariant, affine connection coefficients, curvature tensor, Weyl, Thomas
** Math. Subj. Classification:** 53A55, 53B05, 53C15
1 Introduction
This paper is devoted to generalize the Thomas projective parameter [15] and the Weyl projective tensor [17] as invariants of a mapping of an affine connection space. These invariants are primary generalized in [16] but it is obtained these invariants are not unique ones in this paper. Therefore, we are interested to obtain some invariants of geometric mappings different of the invariants from [16] in this paper.
1.1 Spaces of affine connection
An -dimensional manifold equipped with an affine connection with torsion is called the non-symmetric affine connection space . The affine connection coefficients of the affine connection are and they are non-symmetric by indices and .
The geometrical object
[TABLE]
satisfies the equation
[TABLE]
so it is the affine connection coefficient of a symmetric affine connection space .
The manifold equipped with an affine connection whose coefficients are is the associated space (of the space ).
There is one kind of covariant derivation with regard to a symmetric affine connection:
[TABLE]
for a tensor of the type and the partial derivative denoted by comma.
From the corresponding Ricci-type identity, it is obtained one curvature tensor of the associated space :
[TABLE]
Special symmetric affine connection spaces are Riemannian spaces whose affine connection coefficients are the corresponding Christoffel symbols of the second kind.
Many authors have developed the theory of symmetric affine connection spaces and mappings between them. Some of them are J. Mikeš [9, 2, 12, 8, 11, 10, 1, 3], N. S. Sinyukov [13], V. E. Berezovski [9, 11, 2, 1, 3], L. P. Eisenhart [4] and many others. M. S. Stanković (see [14]) obtained an invariant of an almost geodesic mapping of a non-symmetric affine connection space from the corresponding transformation of the curvature tensor (1.3).
1.2 Motivation
H. Weyl [17] and T. Y. Thomas [15] obtained invariants of geodesic mappings of a symmetric affine connection space. J. Mikeš with his research group [9, 2, 12, 8, 11, 10, 1, 3], N. S. Sinyukov [13], and many other authors have continued the process of generalization of these invariants.
The search for general formula for invariants of geometric mappings is started in [16]. The basic invariants of geometric mappings are obtained in this paper. It is also studied a special case in that paper. In this special case, it is obtained basic invariants of a mapping but the author founded some other invariants different of the basic ones. We are interested to obtain some of these invariants which are not basic in this paper.
The invariants which we are interested to develop in this paper are
- •
The generalized Thomas projective parameter [15]:
[TABLE]
- •
The Weyl projective tensor [17]:
[TABLE]
In a Riemannian space , the Weyl projective tensor (1.5) reduces to
[TABLE]
2 Reminder on basic invariants
Let be a mapping between non-symmetric affine connection spaces and . The deformation tensor of this mapping satisfies the corresponding equation [16]
[TABLE]
for geometrical objects of the type such that .
After symmetrizing the equation (2.1) by indices and , one gets
[TABLE]
With regard to the last result, it is obtained three kinds of invariants of the mapping in [16]. In this paper, we are interested to generalize just invariants of the second kind. The basic invariants which we will generalize are:
[TABLE]
for . The invariant (2.3) is the basic invariant of the mapping of the Thomas type but the invariant (2.4) is the basic invariant of the mapping of the Weyl type.
3 Derived invariants
In general, the geometrical object from the equation (2.1) has the form
[TABLE]
for , -forms , an affinor , a covariant tensor symmetric by indices and and a contra-variant vector .
Remark 3.1**.**
The geometrical objects , , are linearly independent. Otherwise, there would not be necessary three constants .
With regard to the equation (3.1), we get
[TABLE]
It holds the following theorem:
Theorem 3.1**.**
Let be a geometric mapping. The geometrical objects
[TABLE]
for
[TABLE]
, are the basic invariants of the mapping . ∎
3.1 Invariants in associated space
We will analyze the invariants (3.3, 3.4) of a mapping bellow. From this analyzing, we will obtain some other invariants of the mapping .
After contracting the equality by indices and , we get
[TABLE]
for .
After substituting this equation into the equality , one obtains
[TABLE]
for
[TABLE]
and the corresponding .
Lemma 3.1**.**
Let be a geometric mapping of a non-symmetric affine connection space . The geometrical object (3.8) is an invariant of the mapping . ∎
Corollary 3.1**.**
The invariant (3.8) and the Thomas projective parameter given in the equation (1.4) satisfy the equation
[TABLE]
for the corresponding . ∎
The geometrical object (3.8) is the derived associated invariant of the Thomas type.
Furthermore, from the invariance of the geometrical object (3.4) we obtain
[TABLE]
After contracting this equation by indices and , we get
[TABLE]
From the equations (3.10, 3.11), one obtains
[TABLE]
From the contraction of this result by indices and , we get
[TABLE]
With regard to the equations (3.12, 3.13), we get
[TABLE]
for
[TABLE]
and the corresponding .
Let us test are some summands in the invariant () invariants of the mapping . After contract the equality by indices and , we get
[TABLE]
Hence, the invariant () reduces to
[TABLE]
and the corresponding .
Let us check-out are there invariants of the mapping into the invariant (). After contracting the equality by the indices and , one obtains
[TABLE]
Hereof, the invariant () reduces to
[TABLE]
It holds the following theorem:
Theorem 3.2**.**
Let be a geometric mapping. The geometrical object(3.14)* is an invariant of this mapping. ∎*
Corollary 3.2**.**
The invariant (3.14) and the Weyl projective tensor (1.5) satisfy the equation
[TABLE]
for the corresponding . ∎
The geometrical object (3.14) is the derived associated invariant of the Weyl type.
3.2 -planar mappings
In this part of paper, we will apply the above obtained results. The theoretical part of this application will be search for invariants of conformal mappings. The practical example will be about a transformation of a special Riemannian space.
-planar mappings. A mapping is called the -planar mapping if it is determined with the equation
[TABLE]
for -forms and an affinor .
The basic equation of the inverse mapping is
[TABLE]
Hence, we get the mapping is an -planar mapping for
[TABLE]
Moreover, it holds
[TABLE]
Therefore, the -planar mapping is the case of , in the equation (3.1).
After contracting the equation (3.19) by indices and , one gets
[TABLE]
With regard to the equations (3.1, 3.19, 3.20), we obtain
[TABLE]
for .
From the equation (3.3), it holds that the associated invariant of the Thomas type of the mapping is
[TABLE]
for the generalized Thomas projective parameter from the equation (1.4).
Based on the equation (3.18), we obtain
[TABLE]
i.e. the geometrical objects (3.5, 3.6) reduce to
[TABLE]
Therefore, the invariant (3.4) of the mapping is
[TABLE]
for given in the equation (3.24).
The invariant (3.14) of the -planar mapping is
[TABLE]
for the Weyl projective tensor .
Example 1**.**
In this example, we are aimed to obtain the invariants (3.22, 3.25, 3.26) of an -planar mapping for the Riemannian space determined with the metric tensor
[TABLE]
The corresponding affinor and covariant vector are
[TABLE]
Let be . It is satisfied
[TABLE]
It also holds
[TABLE]
The Christoffel symbols of the second kind of this space are
[TABLE]
and in all other cases.
The generalized Thomas projective parameter of the space is
[TABLE]
Hence, the derived invariant of Thomas type of the mapping is
[TABLE]
for given by the equations (3.35, 3.36).
We have the following cases for the curvature tensor :
[TABLE]
It is also satisfied
[TABLE]
for given in the equations (3.35, 3.36).
Hence, the corresponding invariants of Weyl type of the mapping are
[TABLE]
The reference list from the paper itself. Each links out to its DOI / PubMed record.
- 1[1] V. Berezovski, S. Báscó, J. Mikeš , Almost geodesic mappings of affinely connected spaces that preserve the Riemannian curvature , Annales Mathematicae et Informaticae, 45 (2015) pp. 3–10.
- 2[2] V. Berezovski, S. Báscó, J. Mikeš , Diffeomorphism of Affine Connected Spaces Which Preserved Riemannian and Ricci Curvature Tensors , Miskolc Mathematical Notes, Vol. 18 (2017), No. 1, pp. 117–124.
- 3[3] V. Berezovskij, J. Mikeš , On special almost geodesic mappings of type π 1 subscript 𝜋 1 \pi_{1} of spaces with affine connection , Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica, Vol. 43 (2004), No.1, 21–26.
- 4[4] L. P. Eisenhart , Riemannian Geometry , Princeton University Press, 1926.
- 5[5] A. Einstein , A generalization of the relativistic theory of gravitation , Ann. of. Math., 45 (1945), No. 2, 576–584.
- 6[6] A. Einstein , Bianchi identities in the generalized theory of gravitation , Can. J. Math., (1950), No. 2, 120–128.
- 7[7] A. Einstein , Relativistic Theory of the Non-symmetric Field , Princeton University Press, New Jersey, 1954, 5th edition.
- 8[8] J. Mikeš , Holomorphically Projective Mappings and Their Generalizations , International Journal of Mathematical Sciences, Vol. 89, No. 3, 1998, 1334–1353.
