A procedure is developed to find static solutions for anisotropic fluid spheres
from known static solutions for perfect fluid spheres. The method is used to
obtain four exact analytical solutions of Einstein’s equations for spherically
symmetric self-gravitating distribution of anisotropic matter. The solutions are
matched to the Schwarzschild exterior metric. The physical features of one of
the s... hiện toàn bộ
Symmetry played a central role in the works of E.P. Wigner. He made a great
contribution to the extension and reinterpretation of the concept of symmetry.
He proposed a new classification. The paper investigates in the light of
Wigner’s works how do we see now the classification of physical symmetries.