Error in the estimated core and envelope rotation rates introduced by neglecting NDEs. The errors are shown in terms of the individual uncertainties, σ_Ω, as a function of the large frequency separation, Δν. Synthetic splittings were generated for three different core rotation rates, Ω_core/(2π) = 500, 750, and 1000 nHz, with an envelope rotation rate of Ω_env/(2π) = 50 nHz, indicated by crosses, circles, and squares, respectively. Results for the core and envelope are shown in shades of blue and red, respectively. Models evolve from left to right in this figure.