Cartan's Approach to Second Order Ordinary Differential Equations

In his work on projective connections, Cartan discusses his theory of second order differential euqtions . It is the aim here to look at how a normal projective connection can be constructed and how it relates to the geometry of a single second order differential equation. The calculations are presented in some detail in order to highlight the usage of gauge conditions.

Reign and ritual: crowning of the tsaraesthetics in the interpretation of N.F. Fyodorov

The article is dedicated to the semiosis of the tsar’s crowning ritual in Nikolay Fyodorovich Fyodorov’s «Philosophy of the Common Task». This problem has never been an object of a special research but it helps to get closer to the understanding of ontology of Fyodorov’s aesthetic supramoralism project. His philosophical works «Monarchy», «Aesthetic Supramoralism», «Easter in the Kremlin with Coronation», «About the Kremlin Walls Paintings», «About the Monument to Alexander III…», «For the Forthcoming Coronation» are analyzed in the article. The interpretation particularities of the coronation ritual semiotic system in the context of supramoralism aesthetics are defined. The projective connection of the coronation with governmental social ideal is shown in the article, this ideal was formed in Fyodorov’s Christian universalism. The comparison is made between Fyodorov’s project of the tsar’s crowning ritual and coronation in the Russian Empire ceremonial culture. Fyodorov’s understanding ofthe emperor’s regalia symbolism and meaning of the ancient Byzantianacacius ritual inclusion are disclosed in the article. The analysis of time and space images in Fyodorov’s interpretation allowed seeing liturgic basis of his project aesthetics. The importance of the explanatory and projective ecphrasis is demonstrated in the process of Fyodorov’s interpretation of the monumental visual art that express aesthetic and didactic meaning of the crowning ritual.

Centered planes in the projective connection space

The space of centered planes is considered in the Cartan projec­ti­ve connection space . The space is important because it has con­nec­tion with the Grassmann manifold, which plays an important role in geometry and topology, since it is the basic space of a universal vector bundle. The space is an n-dimensional differentiable manifold with each point of which an n-dimensional projective space containing this point is associated. Thus, the manifold is the base, and the space is the n-dimensional fiber “glued” to the points of the base. A projective space is a quotient space of a linear space with respect to the equivalence (collinearity) of non-zero vectors, that is . The projective space is a manifold of di­men­sion n. In this paper we use the Laptev — Lumiste invariant analytical meth­od of differential geometric studies of the space of centered planes and introduce a fundamental-group connection in the associated bundle . The bundle contains four quotient bundles. It is show that the connection object is a quasi-tensor containing four subquasi-tensors that define connections in the corresponding quotient bundles.

Glued linear connection on surface of the projective space

We consider a surface as a variety of centered planes in a multidi­mensional projective space. A fiber bundle of the linear coframes appears over this manifold. It is important to emphasize the fiber bundle is not the principal bundle. We called it a glued bundle of the linear coframes. A connection is set by the Laptev — Lumiste method in the fiber bundle. The ifferential equations of the connection object components have been found. This leads to a space of the glued linear connection. The expres­sions for a curvature object of the given connection are found in the pa­per. The theorem is proved that the curvature object is a tensor. A condi­tion is found under which the space of the glued linear connection turns into the space of Cartan projective connection. The study uses the Cartan — Laptev method, which is based on cal­culating external differential forms. Moreover, all considerations in the article have a local manner.

Сurvature-torsion tensor for Cartan connection

A Lie group containing a subgroup is considered. Such a group is a principal bundle, a typical fiber of this principal bundle is the subgroup and a base is a homogeneous space, which is obtained by factoring the group by the subgroup. Starting from this group, we constructed structure equations of a space with Cartan connection, which generalizes the Cartan point projective connection, Akivis’s linear projective connection, and a plane projective connection. Structure equations of this Cartan connection, containing the components of the curvature-torsion object, allowed: 1) to show that the curvature-torsion object forms a tensor containing a torsion tensor; 2) to find an analogue of the Bianchi identities such that the curvature-torsion tensor and its Pfaff derivatives satisfy this analogue; 3) to obtain the conditions for the transformation of Pfaffian derivatives of the curvature-torsion tensor into covariant derivatives with respect to the Cartan connection.

Curvature tensor of connection in principal bundle of Cartan's projective connection space

We considered Cartan's projective connection space with structure equations generalizing the structure equations of the projective space and the condition of local projectivity (this condition is an analogue to the equiprojectivity condition in the projective space). The curvature-torsion object of the space is a tensor containing three subtensor: torsion tensor, torsion affine curvature tensor, extended torsion tensor. Cartan's projective connection space is not a space with connection of the principal bundle. The assignment of a connection in the adjoint principal bundle leads to a space with a connection. It is proved that the curvature object of the introduced connection is a tensor.

Dynamical projective curvature in gravitation

By using a projective connection over the space of two-dimensional affine connections, we are able to show that the metric interaction of Polyakov two-dimensional gravity with a coadjoint element arises naturally through the projective Ricci tensor. Through the curvature invariants of Thomas and Whitehead, we are able to define an action that could describe dynamics to the projective connection. We discuss implications of the projective connection in higher dimensions as related to gravitation.

A class of non-holonomic projective connections on sub-Riemannian manifolds

The authors define a semi-symmetric non-holonomic (SSNH)-projective connection on sub-Riemannian manifolds and find an invariant of the SSNH-projective transformation. The authors further derive that a sub-Riemannian manifold is of projective flat if and only if the Schouten curvature tensor of a special SSNH-connection is zero.