Distributions of velocity divergence versus density contrast values for the true (green) and NN-reconstructed (blue) fields in the validation mocks. They are represented as shaded areas bounded by the iso-density contours of the distribution. Going from a darker to lighter hue, the shaded areas contain 50, 90, and 99% of all the points, respectively. The velocity divergence values are rescaled such that the diagonal dotted line marks the linear theory prediction.