1998/04/21 by Karim A. Malik, David Wands, Malik, Karim A. +1
Computer Science · Physics and Astronomy · #Astrophysics (astro-ph) #Black Holes and Theoretical Physics #Computational Physics and Python Applications #Cosmology and Gravitation Theories #FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #astro-ph #gr-qc
paper · pdf · doi:10.48550/arxiv.gr-qc/9804046
4 pages, Revtex, no figures
arxiv created 1998/04/21 · openalex publication_date 1998/04/21 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We show how gauge-invariant cosmological perturbations may be constructed by an unambiguous choice of hypersurface-orthogonal time-like vector field (i.e., time-slicing). This may be defined either in terms of the metric quantities such as curvature or shear, or using some matter field. As an example, we show how linear perturbations in the covariant fluid-flow approach can then be presented in an explicitly gauge-invariant form in the coordinate based formalism.