  We show that in the single component situation all perturbation variables in
the comoving gauge are conformally invariant to all perturbation orders.
Generally we identify a special time slicing, the uniform-conformal
transformation slicing, where all perturbations are again conformally invariant
to all perturbation orders. We apply this result to the delta N formalism, and
show its conformal invariance.

General Relativity and Quantum Cosmology;Cosmology and Nongalactic Astrophysics;High Energy Physics - Phenomenology;High Energy Physics - Theory