Results 71 to 80 of about 3,108 (166)

On the symmetric block design with parameters (153, 57, 21)

Le Matematiche, 2009
In this paper it is proved that:A) Up to isomorphism and duality there are exactly two possible orbital structures for a putative symmetric block design with parameters (153, 57, 21) constructed using the Frobenius group F_{17·16}B) Up to isomorphism and
Rexhep Gjergji
doaj  

Semiconformal symmetry- A new symmetry of the spacetime manifold of the general relativity

, 2019
In this paper we have introduced a new symmetry property of spacetime which is named as semiconformal curvature collineation, and its relationship with other known symmetry properties has been established.
Ahsan, Zafar, Ali, Musavvir, Pundeer, Naeem Ahmad   +2 more
core  

Geometric equations of state in Friedmann-Lema\^{i}tre universes admitting matter and Ricci Collineations

, 2003
As a rule in General Relativity the spacetime metric fixes the Einstein tensor and through the Field Equations (FE) the energy-momentum tensor. However one cannot write the FE explicitly until a class of observers has been considered.
Apostolopoulos, Pantelis S., Tsamparlis, Michael   +1 more
core   +1 more source

Distributed three-dimensional affine formation maneuver control for multiple autonomous underwater vehicles

Zhongguo Jianchuan Yanjiu
ObjectivesTo improve the ability of autonomous underwater vehicle (AUV) formations to perform tasks in complex obstacle scenarios, a distributed three-dimensional affine formation shape maneuver control method is proposed for multi-AUV formations ...
Mingqi YAO, Lin YU, Kai GUO, Yu LU, Lei QIAO   +4 more
doaj   +1 more source

On the general structure of Ricci collineations for type B warped spacetimes

, 2004
A complete study of the structure of Ricci collineations for type B warped spacetimes is carried out. This study can be used as a method to obtain these symetries in such spacetimes.
Apostolopoulos P. S., Camci U., Carot J., Carot J., Carot J., Hall G. S., Hall G. S., J. L. Flores, Katzin G. H., U. Percoco, Y. Parra   +10 more
core   +1 more source

Symmetries of f−associated standard static spacetimes and applications

Journal of the Egyptian Mathematical Society, 2017
The purpose of this note is to study and explore some collineation vector fields on standard static spacetimes If × M(also called f− associated SSST). Conformal vector fields, Ricci and matter collineations are studied.
H.K. El-Sayied, Sameh Shenawy, Noha Syied   +2 more
doaj  

Notes on Cooperstein Ovoids in Finite Geometries of Type 𝖤_6,1

Mathematics
A Cooperstein ovoid is a set of q8+q4+1 pairwise non-collinear points in the Lie incidence geometry E6,1(q). They were introduced by Cooperstein twenty-six years ago, motivated by the fact that possible non-existence of them would imply non-existence of ...
Hendrik Van Maldeghem
doaj   +1 more source

Complete collineations revisited [PDF]

Mathematische Annalen, 1999
The space of complete collineations is a compactification of the space of matrices of fixed dimension and rank, whose boundary is a divisor with normal crossings. It was introduced in the 19th century and has been used to solve many enumerative problems.
openaire   +3 more sources

Collineations in a plane with invariant quadric or cubic curves [PDF]

, 1897
Henry S. White
openalex   +1 more source

The characterization of plane collineations in terms of homologous families of lines [PDF]

, 1935
Walter Prenowitz
openalex   +1 more source