“…Evidently, ( 13) is a working assumption. It is the subject of a growing body of work in the cosmology literature either questioning [74][75][76][77][78][79][80] or refining the Risaliti-Lusso prescription [100,101]. 9 In particular, it has been argued in [80] that the Risaliti-Lusso QSOs are impacted by extinction, but this effect may not be large enough to explain the discrepancy seen in the Hubble diagram [102].…”