Results 21 to 30 of about 3,108 (166)
ON THE DEFINITION OF MATTER COLLINEATIONS [PDF]
Modern Physics Letters A, 2009 It is shown that when the stress–energy tensor of a spacetime is diagonal and is written in the mixed form, its collineations admit infinite dimensional Lie algebras except possibly in the case when the tensor depends on all the spacetime coordinates. The result can be extended for more general second rank tensors.
Asghar Qadir, Khalid Saifullah
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Classification of Spherically Symmetric Static Spacetimes according to their Matter Collineations [PDF]
, 2003 The spherically symmetric static spacetimes are classified according to their matter collineations. These are studied when the energy-momentum tensor is degenerate and also when it is non-degenerate.
A. A. Coley +19 more
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LDPC codes from Singer cycles [PDF]
, 2007 The main goal of coding theory is to devise efficient systems to exploit the full capacity of a communication channel, thus achieving an arbitrarily small error probability. Low Density Parity Check (LDPC) codes are a family of block codes--characterised
Angelo Sonnino +22 more
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Cubic Extensions of Flag-Transitive Planes, I. Even Order
International Journal of Mathematics and Mathematical Sciences, 2001 The collineation groups of even order translation planes which are cubic extensions of flag-transitive planes are determined.
Yutaka Hiramine +2 more
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International Journal of Mathematics and Mathematical Sciences, 1984 In this paper we continue the study of projective planes which admit collineation groups of low rank (Kallaher [1] and Bachmann [2,3]). A rank 5 collineation group of a projective plane ℙ of order n≠3 is proved to be flag-transitive. As in the rank 3 and
Otto Bachmann
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On singular projective deformations of two second class totally focal pseudocongruences of planes
International Journal of Mathematics and Mathematical Sciences, 1988 Let C:L→L¯ be a projective deformation of the second order of two totally focal pseudocongruences L and L¯ of (m−1)-planes in projective spaces Pn and P¯n, 2m−1 ...
Ludmila Goldberg
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Base subsets of polar Grassmannians [PDF]
, 2006 Let $\Delta$ be a thick building of type $\textsf{X}_{n}=\textsf{C}_{n},\textsf{D}_{n}$. Let also ${\mathcal G}_k$ be the Grassmannian of $k$-dimensional singular subspaces of the associated polar space $\Pi$ (of rank $n$). We write ${\mathfrak G}_k$ for
Pankov, Mark
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Approximate Lie Symmetry Conditions of Autoparallels and Geodesics
Abstract and Applied Analysis, Volume 2020, Issue 1, 2020., 2020 This paper is devoted to the study of approximate Lie point symmetries of general autoparallel systems. The significance of such systems is that they characterize the equations of motion of a Riemannian space under an affine parametrization. In particular, we formulate the first‐order symmetry determining equations based on geometric requirements and ...
Sameerah Jamal, Shi Liang Wu
wiley +1 more source
Some geometric aspects of finite abelian groups [PDF]
Rendiconti di Matematica e delle Sue Applicazioni, 2006 Let Π be a finite projective plane admitting a large abelian collineation group. It is well known that this situation may be studied by algebraic means (via a representation by suitable types of difference sets), namely using group rings and algebraic ...
Dina Ghinelli, Dieter Jungnickel
doaj
International Journal of Mathematics and Mathematical Sciences, 2002 Generalizations of the Johnson parallelisms are given using an index m subgroup of a Pappian central collineation group. The parallelisms, called m-parallelisms, are constructed and the isomorphisms classes are discussed.
Norman L. Johnson, Rolando Pomareda
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