## Eulerian and Lagrangian reconstruction method of cosmological
velocity and density fields

*Adi Nusser*, Technion, Haifa

Given the current distribution of matter in a cosmological
background, the corresponding velocity field and the initial
conditions can be reconstructed assuming tiny primordial
fluctuations. After a short outline of dynamics in an expanding
background, several classes of reconstruction methods will be
described. The focus will be on the Euler-Zel'dovich equation and
the least action principle based methods.