4,249 research outputs found
Matrix Lie groups as 3-dimensional almost contact B-metric manifolds
The object of investigation are Lie groups considered as almost contact
B-metric manifolds of the lowest dimension three. It is established a
correspondence of all basic-class-manifolds of the Ganchev-Mihova-Gribachev
classification of the studied manifolds and the explicit matrix representation
of Lie groups. Some known Lie groups are equiped with almost contact B-metric
structure of different types
Totally real submanifolds of -Manifolds
The present paper deals with the study of totally real submanifolds and
-totally real submanifolds of -manifolds with respect to
Levi-Civita connection as well as quarter symmetric metric connection. It is
proved that scalar curvature of -totally real submanifolds of
-manifold with respect to both the said connections are same.Comment: 11 page
LEIBNIZ\u2019S MIRROR THESIS. SOLIPSISM, PRIVATE PERSPECTIVES AND CONCEPTUAL HOLISM
One of the symbolic images to which Leibniz constantly entrusted the synthesis of his philosophy regards the idea of considering one and the same city from various visual perspectives. Such an image is diffused throughout all Leibniz\u2019s writings and clearly reflects the philosopher\u2019s interest for matters regarding perspective as well as optical phenomena. The point of view of its inhabitants can therefore be compared to a mirror that reflects some different portions of reality. But what do the city-viewers really see? Do they all see exactly the same thing? And assuming the plurality of points of view, how one can be sure that they share the same representative content? The paper presented here tries to offer a plausible interpretation of this topic also by linking different and somehow remote Leibnizian doctrines together
On Almost Paracontact Almost Paracomplex Riemannian Manifolds
Almost paracontact manifolds of an odd dimension having an almost paracomplex
structure on the paracontact distribution are studied. The components of the
fundamental (0,3)-tensor, derived by the covariant derivative of the structure
endomorphism and the metric on the considered manifolds in each of the basic
classes, are obtained. Then, the case of the lowest dimension 3 of these
manifolds is considered. An associated tensor of the Nijenhuis tensor is
introduced and the studied manifolds are characterized with respect to this
pair of tensors. Moreover, cases of paracontact and para-Sasakian types are
commented. A family of examples is given.Comment: 18 pages, 2 table
Inflationary RSII Model with a Matter in the Bulk and Exponential Potential of Tachyon Field
In this paper we study a tachyon cosmological model based on dynamics of a
3-brane in the second Randall-Sundrum (RSII) model extended to include matter
in the bulk. The presence of matter in the bulk changes warp factor which leads
to modification of inflationary dynamics. The additional brane behaves
effectively as a tachyon. We calculate numerically observation parameters of
inflation: the scalar spectral index () and the tensor-to-scalar ratio
() for the exponential potential of tachyon field.Comment: 9 pages, 1 figure, will be published in the Special Issue of Facta
Universitatis, Series: Physics, Chemistry and Technology devoted to the
SEENET-MTP Balkan Workshop BSW2018 (3-14 June 2018
Frequently hypercyclic abstract higher-order differential equations
In this note, we analyze frequently hypercyclic solutions of abstract
higher-order differential equations in separable infinite-dimensional complex
Banach spaces. We essentially apply results from the theory of -regularized
semigroups, providing several illustrative examples and possible applications
Cosmological flows on hyperbolic surfaces
We outline the geometric formulation of cosmological flows for FLRW models
with scalar matter as well as certain aspects which arise in their study with
methods originating from the geometric theory of dynamical systems. We briefly
summarize certain results of numerical analysis which we carried out when the
scalar manifold of the model is a hyperbolic surface of infinite area.Comment: 10 pages, conference proceeding
Canonical approach to the closed string noncommutativity
We consider the closed string moving in the weakly curved background and its
totally T-dualized background. Using T-duality transformation laws, we find the
structure of the Poisson brackets in the T-dual space corresponding to the
fundamental Poisson brackets in the original theory. From this structure we
obtain that the commutative original theory is equivalent to the
non-commutative T-dual theory, whose Poisson brackets are proportional to the
background fluxes times winding and momenta numbers. The non-commutative theory
of the present article is more nongeometrical then T-folds and in the case of
three space-time dimensions corresponds to the nongeometric space-time with
-flux.Comment: We add the Sec. 4. where we compared our results with previous ones.
We also improved Abstract, Introduction and Conclusion as described above. In
addition, we corrected all typos and grammatical errors we notice
H-exponential change of Finsler metric
In this paper, we studied a Finsler space whose metric is given by an
h-exponential change and obtain the Cartan connection coefficients for the
change. We also find the necessary and sufficient condition for an
h-exponential change of Finsler metric to be projective
Constraining Scalar-Tensor gravity models by S2 star orbits around the Galactic Center
The aim of our investigation is to derive a particular theory among the class
of scalar-tensor(ST) theories of gravity, and then to test it by studying
kinematics and dynamics of S-stars around supermassive black hole (BH) at
Galactic Center (GC). We also discuss the Newtonian limit of this class of ST
theories of gravity, as well as its parameters. We compare the observed orbit
of S2 star with our simulated orbit which we obtained theoretically with the
derived ST potential and constrained the parameters. Using the obtained best
fit parameters we calculated orbital precession of S2 star in ST gravity,and
found that it has the same direction as in General Relativity (GR), but causes
much larger pericenter shift.Comment: 13 pages, 1 table, 6 figures. Accepted for publication in Facta
Universitatis: Series Phys. Chem. Tech. (Invited lecture at Balkan Workshop
2018
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