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Ljubica S. Velimirović

Bio: Ljubica S. Velimirović is an academic researcher from University of Niš. The author has contributed to research in topics: Infinitesimal & Affine connection. The author has an hindex of 11, co-authored 49 publications receiving 342 citations.


Papers
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Journal ArticleDOI
TL;DR: In this article, generalized Kahlerian spaces of the first kind were defined, and for them they were considered hollomorphically projective mappings with invariant complex structure.
Abstract: In this paper we define generalized Kahlerian spaces of the first kind ( $$ G_1^K N $$ ) given by (2.1)–(2.3). For them we consider hollomorphically projective mappings with invariant complex structure. Also, we consider equitorsion geodesic mapping between these two spaces ( $$ G_1^K N $$ and $$ G_1^{\bar K} N $$ ) and for them we find invariant geometric objects.

35 citations

Journal ArticleDOI
TL;DR: In this paper, the authors investigated holomorphically projective mappings of generalized Kahlerian spaces and obtained five invariant geometric objects for these mappings, which are invariant to equitorsion.
Abstract: In this paper we investigate holomorphically projective mappings of generalized Kahlerian spaces. In the case of equitorsion holomorphically projective mappings of generalized Kahlerian spaces we obtain five invariant geometric objects for these mappings.

31 citations

Journal ArticleDOI
TL;DR: In this article, the authors introduced spacetimes with semisymmetric energy-momentum tensors and characterized the perfect fluid spacetime with semi-measure tensors.
Abstract: The object of the present paper is to introduce spacetimes with semisymmetric energy-momentum tensor. At first we consider the relation R(X,Y)⋅T=0, that is, the energy-momentum tensor T of type (0,2) is semisymmetric. It is shown that in a general relativistic spacetime if the energy-momentum tensor is semisymmetric, then the spacetime is also Ricci semisymmetric and the converse is also true. Next we characterize the perfect fluid spacetime with semisymmetric energy-momentum tensor. Then, we consider conformally flat spacetime with semisymmetric energy-momentum tensor. Finally, we cited some examples of spacetimes admitting semisymmetric energy-momentum tensor.

26 citations

Journal ArticleDOI
TL;DR: Change of the Willmore energy, as the special case of elastic bending energy, under infinitesimal bending of the vesicle membrane is discussed and it is found that theWillmore energy of a boundary-free surface is stationary under an infiniteimal bending.
Abstract: Change of the Willmore energy, as the special case of elastic bending energy, under infinitesimal bending of the vesicle membrane is discussed. A membrane is thought of as a smooth surface in R^3 because its thickness is much smaller than its lateral dimension. Variation of the Willmore energy at the surface point under infinitesimal bending of that surface, as well as the condition for the stationarity of the Willmore energy are given. Some examples are visualized. Variation of the Willmore energy of a compact path-connected smooth surface in the Euclidean 3-space is reduced to a line integral of a special vector field and it is found that the Willmore energy of a boundary-free surface is stationary under an infinitesimal bending. Also, the Willmore energy of a minimal surface is stationary under its infinitesimal bending.

19 citations

Journal ArticleDOI
TL;DR: Tensor calculus and differential geometry are applied to consider shell structure to examine the stationarity of the Willmore energy under infinitesimal deformations of the surfaces in @?^3 and give a new proof of a well-known theorem (that reads that the total mean curvature of a surface is stationary under an infiniteimal bending), applying tensor calculus.
Abstract: In this paper we apply tensor calculus and differential geometry to consider shell structure. Using tensor calculus we examine the stationarity of the Willmore energy under infinitesimal deformations of the surfaces in @?^3. We obtain the class of the surfaces which does not change its Willmore energy under infinitesimal deformations. In particular, a special kind of deformation is considered-infinitesimal bending which preserves the arc length. The change of the Willmore energy under such deformations is determined. Also, we give a new proof of a well-known theorem (that reads that the total mean curvature of a surface is stationary under an infinitesimal bending), applying tensor calculus.

19 citations


Cited by
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01 Jan 1978
TL;DR: This ebook is the first authorized digital version of Kernighan and Ritchie's 1988 classic, The C Programming Language (2nd Ed.), and is a "must-have" reference for every serious programmer's digital library.
Abstract: This ebook is the first authorized digital version of Kernighan and Ritchie's 1988 classic, The C Programming Language (2nd Ed.). One of the best-selling programming books published in the last fifty years, "K&R" has been called everything from the "bible" to "a landmark in computer science" and it has influenced generations of programmers. Available now for all leading ebook platforms, this concise and beautifully written text is a "must-have" reference for every serious programmers digital library. As modestly described by the authors in the Preface to the First Edition, this "is not an introductory programming manual; it assumes some familiarity with basic programming concepts like variables, assignment statements, loops, and functions. Nonetheless, a novice programmer should be able to read along and pick up the language, although access to a more knowledgeable colleague will help."

2,120 citations

01 Jan 2005
TL;DR: The speziellen Relativitatstheorie liegt folgendes Postulat zugrunde, welchem auch durch die Galilei-Newtonsche Mechanik Genuge geleistet wird: Wird ein Koordinatensystem K so gewahlt, das in bezug auf dasselbe die physikalischen Gesetze in ihrer einfachsten Form gelten, so gelten dieselben Gesetzes auch in Bez
Abstract: Der speziellen Relativitatstheorie liegt folgendes Postulat zugrunde, welchem auch durch die Galilei-Newtonsche Mechanik Genuge geleistet wird: Wird ein Koordinatensystem K so gewahlt, das in bezug auf dasselbe die physikalischen Gesetze in ihrer einfachsten Form gelten, so gelten dieselben Gesetze auch in Bezug auf jedes andere Koordinatensystem K′, das relativ zu K in gleichformiger Translationsbewegung begriffen ist. Dieses Postulat nennen wir „spezielles Relativitatsprinzip“. Durch das Wort „speziell“ soll angedeutet werden, das das Prinzip auf den Fall beschrankt ist, das K′ eine gleichformige Translationsbewegung gegen K ausfuhrt, das sich aber die Gleichwertigkeit von K′ und K nicht auf den Fall ungleichformiger Bewegung von K′ gegen K erstreckt.

183 citations