ORIGAMI: Delineating Cosmic Structures with Phase-Space Folds
  Structures like galaxies and filaments of galaxies in the Universe come about
from the origami-like folding of an initially flat three-dimensional manifold
in 6D phase space. The ORIGAMI method identifies these structures in a
cosmological simulation, delineating the structures according to their outer
folds. Structure identification is a crucial step in comparing cosmological
simulations to observed maps of the Universe. The ORIGAMI definition is
objective, dynamical and geometric: filament, wall and void particles are
classified according to the number of orthogonal axes along which dark-matter
streams have crossed. Here, we briefly review these ideas, and speculate on how
ORIGAMI might be useful to find cosmic voids.
