“…There are many results which consider notions other than smoothness and strong convexity for first-order methods. Some examples of this is work on star-convexity [GG17, NGGD18, HSS20], quasi-strong convexity [NNG19], semi-convexity [VNP07], the quadratic growth condition [Ani00], the error bound property [LT93,FHKO10], restricted strong convexity [ZY13,ZC15] and Hölder continuity [ZY13,DGN14,Yas16,Gri19]. However, we are unaware of notions of fine-grained condition numbers for non-linear or stochastic problems appearing previously in the literature.…”