Forecasted constraints in the Q_n–Ω_M plane for two choices of n. The black solid curves show the one, two, and three sigma confidence levels in the two-dimensional plane, while the color map depicts the reduced chi-square. Top and bottom panels correspond to n = 1 and n = 1/2, respectively. Left side panels: forecasts for the combination of simulated ELT redshift drift and WFIRST supernova measurements, while for the right side panels a Planck-like prior on the matter density has been added to this data.