ν_max–Δν_obs relation for Kepler (blue pluses) and OGLE (black symbols) AGB and RGB stars. The red solid lines indicate the isomass levels 1 and 2 M_⊙, in their domain of validity. The dotted lines indicate isolines of the number n_max = ν_max/Δν_obs. The vertical green dot-dashed line shows the region where the oscillation regime changes. Typical uncertainties at low and large ν_max for Kepler data are indicated by the 1-σ error boxes.