Isotropic N-point basis functions and their properties

Abstract Isotropic functions of positions r 1 , 2 … N , i.e. invariant under simultaneous rotations all the coordinates, are conveniently formed using spherical harmonics and Clebsch–Gordan coefficients. An orthonormal basis such provides a formalism suitable for analyzing isotropic distributions as those that arise in cosmology, instance clustering galaxies revealed by large-scale structure surveys. The algebraic properties expressed terms 6- j 9- symbols. calculation relations among is facilitated ‘Yutsis’ diagrams addition recoupling angular momenta.