No abstract available

No abstract available

[en] Poincare gauge theory is derived from a linear theory by the method suggested by Gupta for deriving Einstein's general relativity from the linear theory of a spin-2 field. Nonlinearity is introduced by requiring that a set of tensor fields be coupled to the Noether currents of the Poincare group (energy-momentum and spin). (author)

[en] The equality of the symmetrized Noether stress--energy tensor (Belinfante's tensor) and the canonical stress--energy tensor (functional derivative of the Lagrangian density with respect to the metric) is established by methods based on the formalism of tetrads and Ricci rotation coefficients. The result holds for any Lagrangian which contains no derivatives of the fields higher than first order

[en] A formalism is developed which admits particles faster than light and reference frames faster than light and as fast as light. It is fully consistent with the physical principles of special relativity. The necessity of introducing imaginary quantities does not arise. It does not encounter any difficulties with the principle of causality if it is reasonably interpreted

No abstract available

No abstract available

[en] The metric-affine gravitational theory is shown to be the gauge theory of the affine group, or equivalently, the gauge theory of the group GL(4,R) of tetrad deformations in a space-time with a locally Minkowskian metric. The identities of the metric-affine theory, and the relationship between them and those of general relativity and Sciama-Kibble theory, are derived. (Auth.)

No abstract available

[en] It is shown that the Bargmann-Wigner equations can be written in an SO(4,2)-covariant form. As well as the Lorentz rotations, the SO(4,2) group contains a space-inversion and a time-reflection operator (which are different from the usual ones). It also contains the Foldy-Wouthuysen and Cini-Touschek transformations. The spin-s theory for the massive and massless cases, and also a set of Bargmann-Wigner equations corresponding to space-like four-momentum, are all given by the same SO(4,2)-covariant equations, and their solutions can be obtained by transforming the solutions corresponding to the special 'gauge' in which the four-momentum vanishes. (author)