279 research outputs found
The Killing tensors on an -dimensional manifold with -structure
In this paper we solve the problem of finding integrals of equations
determining the Killing tensors on an -dimensional differentiable manifold
endowed with an equiaffine -structure and discuss possible
applications of obtained results in Riemannian geometry
The Seven Classes of the Einstein Equations
In current paper we refer to the geometrical classification of the Einstein
equations which has been developed by one of the authors of this paper. This
classification was based on the classical theory for decomposition of the
tensor product of representations into irreducible components, which is studied
in the elementary representation theory for orthogonal groups. We return to
this result for more detailed investigation of classes of the Einstein
equations.Comment: 9page
From the Ricci flow evolution equation to vanishing theorems for Ricci solitons
In the paper, we study evolution equations of the scalar and Ricci curvatures
under the Hamilton's Ricci flow on a closed manifold and on a complete
noncompact manifold. In particular, we study conditions when the Ricci flow is
trivial and the Ricci soliton is Ricci flat or Einstein.Comment: 10 page
Geometry in the large of the kernel of Lichnerowicz Laplacians and its applications
There are very few general theorems on the kernel of the well-known
Lichnerowicz Laplacian. In the present article we consider the geometry of the
kernel of this operator restricted to covariant (not necessarily symmetric or
skew-symmetric) tensors. Our approach is based on the analytical method, due to
Bochner, of proving vanishing theorems for the null space of Laplace operator.
In particular, we pay special attention to the kernel of the Lichnerowicz
Laplacian on Riemannian symmetric spaces of compact and noncompact types. In
conclusion, we give some applications to the theories of infinitesimal Einstein
deformations and the stability of Einstein manifolds.Comment: 19 page
A Method with Feedback for Aggregation of Group Incomplete Pair-Wise Comparisons
A method for aggregation of expert estimates in small groups is proposed. The
method is based on combinatorial approach to decomposition of pair-wise
comparison matrices and to processing of expert data. It also uses the basic
principles of Analytic Hierarchy/Network Process approaches, such as building
of criteria hierarchy to decompose and describe the problem, and evaluation of
objects by means of pair-wise comparisons. It allows to derive priorities based
on group incomplete pair-wise comparisons and to organize feedback with experts
in order to achieve sufficient agreement of their estimates. Double entropy
inter-rater index is suggested for usage as agreement measure. Every expert is
given an opportunity to use the scale, in which the degree of detail (number of
points/grades) most adequately reflects this expert's competence in the issue
under consideration, for every single pair comparison. The method takes all
conceptual levels of individual expert competence (subject domain, specific
problem, individual pair-wise comparison matrix, separate pair-wise comparison)
into consideration. The method is intended to be used in the process of
strategic planning in weakly-structured subject domains.Comment: 13 pages, 6 figure
A remark on the Laplacian operator which acts on symmetric tensors
More than forty years ago J. H. Samson has defined the Laplacian
acting on the space of symmetric covariant -tensors on an
-dimensional Riemannian manifold . This operator is an analogue of
the well known Hodge-de Rham Laplacian which acts on the space of
exterior differential -forms () on . In the present
paper we will prove that for the operator is the
Yano rough Laplacian and show its spectrum properties on a compact Riemannian
manifold.Comment: Riemannian manifold, second order elliptic differential operator on
1-forms, eigenvalues and eigenform
Conformal Killing forms on complete Riemannian manifolds with nonpositive curvature operator
We give a classification for connected complete locally irreducible
Riemannian manifolds with nonpositive curvature operator, which admit a nonzero
closed or co-closed conformal Killing form. Moreover, we prove
vanishing theorems for closed and co-closed conformal Killing forms on
some complete Riemannian manifolds
Usage of Decision Support Systems for Conflicts Modelling during Information Operations Recognition
Application of decision support systems for conflict modeling in information
operations recognition is presented. An information operation is considered as
a complex weakly structured system. The model of conflict between two subjects
is proposed based on the second-order rank reflexive model. The method is
described for construction of the design pattern for knowledge bases of
decision support systems. In the talk, the methodology is proposed for using of
decision support systems for modeling of conflicts in information operations
recognition based on the use of expert knowledge and content monitoring.Comment: 8 pages, 1 figur
From harmonic mappings to Ricci solitons
The paper is devoted to the study of the global geometries of harmonic
mappings and infinitesimal harmonic transformations and presents their
applications to the theory of Ricci solitons
Comparing Efficiency of Expert Data Aggregation Methods
Expert estimation of objects takes place when there are no benchmark values
of object weights, but these weights still have to be defined. That is why it
is problematic to define the efficiency of expert estimation methods. We
propose to define efficiency of such methods based on stability of their
results under perturbations of input data. We compare two modifications of
combinatorial method of expert data aggregation (spanning tree enumeration).
Using the example of these two methods, we illustrate two approaches to
efficiency evaluation. The first approach is based on usage of real data,
obtained through estimation of a set of model objects by a group of experts.
The second approach is based on simulation of the whole expert examination
cycle (including expert estimates). During evaluation of efficiency of the two
listed modifications of combinatorial expert data aggregation method the
simulation-based approach proved more robust and credible. Our experimental
study confirms that if weights of spanning trees are taken into consideration,
the results of combinatorial data aggregation method become more stable. So,
weighted spanning tree enumeration method has an advantage over non-weighted
method (and, consequently, over logarithmic least squares and row geometric
mean methods).Comment: 16 pages, 6 figures, 5 table
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