1,721,961 research outputs found
1960 -- Correspondence, Miscellaneous -- letter, 1960-01-14
No full textLetter from Barrett, John D. to Sabin, Albert B. dated 1960-01-14.Sabin Collection Fair Use Policy</a
Mathematical source references
No full textThis list of references is intended to be a convenient reference source for those interested in the historical origin of common mathematical ideas, The topics mentioned are mostly those met in a degree course in mathematics. For each entry the list attempts to give an exact source reference with comments about priority. There are now available other historical reference sources for mathematics on the internet but with a different style of presentation.<br/
Minkowski space-time and hyperbolic geometry
No full textIt has become generally recognized that hyperbolic (i.e. Lobachevskian) space can be represented upon one sheet of a two-sheeted cylindrical hyperboloid in Minkowski space-time. This paper aims to clarify the derivation of this result and to describe some further related ideas. Firstly a simple justification is given of the stated property, which seems somewhat lacking in the literature. This is straightforward once it is shown that differential displacements on the hyperboloid surface are space-like elements in Minkowski space-time. This needs certain preliminary remarks on Minkowski space-time.Two other derivations are given which are valid in any pseudo-Euclidean space of the same type.An alternative view comes from regarding Minkowski space-time projectively as a velocity space. This is possible with Minkowski's original representation but is best seen when Minkowski space-time is regarded differentially as a special case of the metric of General Relativity. Here the space may also be considered as differential space-time in the sense of Minkowski'. It may be considered as a projective space and in this case, as a velocity space which is a Lobachevsky space with hyperboloid representation. Projection of the hyperboloid to a disc or spherical ball gives an associated Beltrami-Klein representation of velocity space. This geometrical representation has important application in physics being related to the hyperbolic theory of Special Relativity which was first proposed by Varićak in 1910 following Einstein's original 1905 paper. The Cayley metric for the velocity space representation leads to relativistic addition of two velocities. The paper emphasizes the importance of Weierstrass coordinates as they are highly appropriate to the relativity application. They also show the close relation between the hyperboloid representation and the equivalent spherical one, the hyperbolic space being then regarded as a sphere of imaginary radius which has historically been a guiding idea and one closely related to Special Relativity.<br/
La variance de la fréquence des rapports sexuels
No full textBarrett John C. La variance de la fréquence des rapports sexuels. In: Population, 33ᵉ année, n°3, 1978. pp. 747-749
Délais de conception selon l'âge du père et de la mère
No full textBarrett John-C. Délais de conception selon l'âge du père et de la mère. In: Population, 36ᵉ année, n°4-5, 1981. pp. 946-949
The hyperbolic theory of special relativity
No full textThe book is based largely on the author's researches presented at conferences in the period 1992 onwards. It is a historically based exposition and an extension of the hyperbolic version of special relativity first proposed by Varićak (1910 etc) and others not long after the appearance of the early papers of Einstein and Minkowski. The book's approach puts emphasis on the concept of hyperbolic velocity (scaled rapidity) and in this respect differs markedly from the gyro theory of Ungar. New formulations are given in optics relating hyperbolic velocity with logarithmic redshift and in dynamics including a reformulation of Newton's 2nd law in terms of hyperbolic acceleration so avoiding velocity-dependent mass. The concept of differential Minkowski space is introduced and related to the hyperbolic theory and to Carathéodory's axiomatic approach to the special theory
In the hyperbolic theory of special relativity is space also hyperbolic?
No full textIn the hyperbolic theory of special relativity the space of velocities, the kinematic space, is hyperbolic of radius of negative curvature c the velocity of light. Space itself could be either Euclidean or hyperbolic. Whether space is hyperbolic is an important question for cosmology, philosophy and the axioms of special relativity. This paper considers consequences of it being hyperbolic including an estimate of the deviation from parallelism at terrestrial distances
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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