Abundances in GN-z11 and other objects, compared with models. Panel a: diagram log(N/O) versus log(O/H)+12: “fiducial” (pink filled) and “conservative” (pink dashed border) error boxes for GN-z11 (Cameron et al. 2023). Black open square with error bars: abundances from Senchyna et al. (2023). Colored squares: average abundances ratios in the ejecta of intermediate mass AGB stars (Ventura et al. 2013). Metallicities in mass fraction Z and masses (from 7.5 to 4 M_⊙) are labelled in the figure. Asterisks: initial O/H and N/O abundances of the models (see Table 1 and Ventura et al. 2013). Solar symbol is placed at the values corresponding to solar abundances. Black lines: examples of dilution of the ejecta (of the 4 and 7 M_⊙ at Z = 0.002) with gas having the initial chemical composition; triangles are marking 20, 40, 60 and 80% of diluting pristine gas. Thistle squares with error bars: abundances observed in low metallicity galaxies at z = 0.3–0.4 (Izotov et al. 2023) and in the local compact galaxies from the SLOAN (Izotov et al. 2012). At the bottom: upper (full) and lower (dashed) envelope of the chemical evolution models by Vincenzo et al. (2016). Other star forming galaxies at high redshift having high log(N/O) are shown as colored triangles and are identified in the labels. Panel b: diagram log(C/O) versus log(O/H)+12. Symbols and lines as in panel a.