As a function of stellar mass, measured g − i color for isolated E galaxies. The black line shows Eq. (15) to separate red and blue galaxies. The open black stars and open black triangles show the blue SF isolated ellipticals from the SIG and L16 samples, respectively. The color bars correspond to the Q_LSS parameter (top panel), η_k,LSS parameter (middle panel), and the distance to the fifth nearest neighbor galaxy out to 5 Mpc (bottom panel). The total number of galaxies is indicated in each panel.